2 Bundle of old SSLeay documentation files [OBSOLETE!]
4 *** WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! ***
6 OBSOLETE means that nothing in this document should be trusted. This
7 document is provided mostly for historical purposes (it wasn't even up
8 to date at the time SSLeay 0.8.1 was released) and as inspiration. If
9 you copy some snippet of code from this document, please _check_ that
10 it really is correct from all points of view. For example, you can
11 check with the other documents in this directory tree, or by comparing
12 with relevant parts of the include files.
14 People have done the mistake of trusting what's written here. Please
17 *** WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! ***
20 ==== readme ========================================================
22 This is the old 0.6.6 docuementation. Most of the cipher stuff is still
23 relevent but I'm working (very slowly) on new docuemtation.
24 The current version can be found online at
26 http://www.cryptsoft.com/ssleay/doc
28 ==== API.doc ========================================================
30 SSL - SSLv2/v3/v23 etc.
32 BIO - methods and how they plug together
34 MEM - memory allocation callback
36 CRYPTO - locking for threads
38 EVP - Ciphers/Digests/signatures
42 X509 - certificate retrieval
46 X509 - X509v3 extensions
48 Objects - adding object identifiers
54 ==== ssl/readme =====================================================
57 This file belongs in ../apps, but I'll leave it here because it deals
58 with SSL :-) It is rather dated but it gives you an idea of how
63 I have been changing things quite a bit and have not fully updated
64 this file, so take what you read with a grain of salt
67 The s_client and s_server programs can be used to test SSL capable
68 IP/port addresses and the verification of the X509 certificates in use
69 by these services. I strongly advise having a look at the code to get
70 an idea of how to use the authentication under SSLeay. Any feedback
71 on changes and improvements would be greatly accepted.
73 This file will probably be gibberish unless you have read
74 rfc1421, rfc1422, rfc1423 and rfc1424 which describe PEM
77 A Brief outline (and examples) how to use them to do so.
80 The environment variable SSL_CIPER is used to specify the prefered
81 cipher to use, play around with setting it's value to combinations of
82 RC4-MD5, EXP-RC4-MD5, CBC-DES-MD5, CBC3-DES-MD5, CFB-DES-NULL
83 in a : separated list.
85 This directory contains 3 X509 certificates which can be used by these programs.
86 client.pem: a file containing a certificate and private key to be used
88 server.pem :a file containing a certificate and private key to be used
90 eay1024.pem:the certificate used to sign client.pem and server.pem.
91 This would be your CA's certificate. There is also a link
92 from the file a8556381.0 to eay1024.PEM. The value a8556381
93 is returned by 'x509 -hash -noout <eay1024.pem' and is the
94 value used by X509 verification routines to 'find' this
95 certificte when search a directory for it.
96 [the above is not true any more, the CA cert is
97 ../certs/testca.pem which is signed by ../certs/mincomca.pem]
99 When testing the s_server, you may get
100 bind: Address already in use
101 errors. These indicate the port is still being held by the unix
102 kernel and you are going to have to wait for it to let go of it. If
103 this is the case, remember to use the port commands on the s_server and
104 s_client to talk on an alternative port.
108 This program can be used to connect to any IP/hostname:port that is
109 talking SSL. Once connected, it will attempt to authenticate the
110 certificate it was passed and if everything works as expected, a 2
111 directional channel will be open. Any text typed will be sent to the
112 other end. type Q<cr> to exit. Flags are as follows.
113 -host arg : Arg is the host or IP address to connect to.
114 -port arg : Arg is the port to connect to (https is 443).
115 -verify arg : Turn on authentication of the server certificate.
116 : Arg specifies the 'depth', this will covered below.
117 -cert arg : The optional certificate to use. This certificate
118 : will be returned to the server if the server
119 : requests it for client authentication.
120 -key arg : The private key that matches the certificate
121 : specified by the -cert option. If this is not
122 : specified (but -cert is), the -cert file will be
123 : searched for the Private key. Both files are
124 : assumed to be in PEM format.
125 -CApath arg : When to look for certificates when 'verifying' the
126 : certificate from the server.
127 -CAfile arg : A file containing certificates to be used for
128 : 'verifying' the server certificate.
129 -reconnect : Once a connection has been made, drop it and
130 : reconnect with same session-id. This is for testing :-).
132 The '-verify n' parameter specifies not only to verify the servers
133 certificate but to also only take notice of 'n' levels. The best way
134 to explain is to show via examples.
136 s_server -cert server.PEM is running.
140 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo server
141 issuer= /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
142 verify error:num=1:unable to get issuer certificate
144 CIPHER is CBC-DES-MD5
145 What has happened is that the 'SSLeay demo server' certificate's
146 issuer ('CA') could not be found but because verify is not on, we
147 don't care and the connection has been made anyway. It is now 'up'
148 using CBC-DES-MD5 mode. This is an unauthenticate secure channel.
149 You may not be talking to the right person but the data going to them
154 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo server
155 issuer= /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
156 verify error:num=1:unable to get issuer certificate
158 CIPHER is CBC-DES-MD5
159 We are 'verifying' but only to depth 0, so since the 'SSLeay demo server'
160 certificate passed the date and checksum, we are happy to proceed.
164 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo server
165 issuer= /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
166 verify error:num=1:unable to get issuer certificate
169 verify error:unable to get issuer certificate
170 In this case we failed to make the connection because we could not
171 authenticate the certificate because we could not find the
174 s_client -verify 1 -CAfile eay1024.PEM
176 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo server
178 depth=1 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
180 CIPHER is CBC-DES-MD5
181 We loaded the certificates from the file eay1024.PEM. Everything
182 checked out and so we made the connection.
184 s_client -verify 1 -CApath .
186 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo server
188 depth=1 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
190 CIPHER is CBC-DES-MD5
191 We looked in out local directory for issuer certificates and 'found'
192 a8556381.0 and so everything is ok.
194 It is worth noting that 'CA' is a self certified certificate. If you
195 are passed one of these, it will fail to 'verify' at depth 0 because
196 we need to lookup the certifier of a certificate from some information
197 that we trust and keep locally.
199 SSL_CIPHER=CBC3-DES-MD5:RC4-MD5
201 s_client -verify 10 -CApath . -reconnect
203 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo server
205 depth=1 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
207 drop the connection and reconnect with the same session id
208 CIPHER is CBC3-DES-MD5
209 This has done a full connection and then re-estabished it with the
210 same session id but a new socket. No RSA stuff occures on the second
211 connection. Note that we said we would prefer to use CBC3-DES-MD5
212 encryption and so, since the server supports it, we are.
216 This program accepts SSL connections on a specified port
217 Once connected, it will estabish an SSL connection and optionaly
218 attempt to authenticate the client. A 2 directional channel will be
219 open. Any text typed will be sent to the other end. Type Q<cr> to exit.
220 Flags are as follows.
221 -port arg : Arg is the port to listen on.
222 -verify arg : Turn on authentication of the client if they have a
223 : certificate. Arg specifies the 'depth'.
224 -Verify arg : Turn on authentication of the client. If they don't
225 : have a valid certificate, drop the connection.
226 -cert arg : The certificate to use. This certificate
227 : will be passed to the client. If it is not
228 : specified, it will default to server.PEM
229 -key arg : The private key that matches the certificate
230 : specified by the -cert option. If this is not
231 : specified (but -cert is), the -cert file will be
232 : searched for the Private key. Both files are
233 : assumed to be in PEM format. Default is server.PEM
234 -CApath arg : When to look for certificates when 'verifying' the
235 : certificate from the client.
236 -CAfile arg : A file containing certificates to be used for
237 : 'verifying' the client certificate.
239 For the following 'demo' I will specify the s_server command and
240 the s_client command and then list the output from the s_server.
244 CIPHER is CBC-DES-MD5
245 Everything up and running
250 CIPHER is CBC-DES-MD5
251 Ok since no certificate was returned and we don't care.
254 ./s_client -cert client.PEM
256 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo client
257 issuer= /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
258 verify error:num=1:unable to get issuer certificate
260 CIPHER is CBC-DES-MD5
261 Ok since we were only verifying to level 0
264 s_client -cert client.PEM
266 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo client
267 issuer= /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
268 verify error:num=1:unable to get issuer certificate
271 verify error:unable to get issuer certificate
272 Bad because we could not authenticate the returned certificate.
274 s_server -verify 4 -CApath .
275 s_client -cert client.PEM
277 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo client
279 depth=1 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
281 CIPHER is CBC-DES-MD5
282 Ok because we could authenticate the returned certificate :-).
284 s_server -Verify 0 -CApath .
288 SSL error:function is:REQUEST_CERTIFICATE
289 :error is :client end did not return a certificate
290 Error because no certificate returned.
292 s_server -Verify 4 -CApath .
293 s_client -cert client.PEM
295 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo client
297 depth=1 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
299 CIPHER is CBC-DES-MD5
300 Full authentication of the client.
302 So in summary to do full authentication of both ends
303 s_server -Verify 9 -CApath .
304 s_client -cert client.PEM -CApath . -verify 9
307 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo client
309 depth=1 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
311 CIPHER is CBC-DES-MD5
314 depth=0 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=SSLeay demo server
316 depth=1 /C=AU/SOP=QLD/O=Mincom Pty. Ltd./OU=CS/CN=CA
318 CIPHER is CBC-DES-MD5
320 For general probing of the 'internet https' servers for the
321 distribution area, run
322 s_client -host www.netscape.com -port 443 -verify 4 -CApath ../rsa/hash
325 and you should be talking to the https server on that host.
327 www.rsa.com was refusing to respond to connections on 443 when I was
334 ==== a_verify.doc ========================================================
336 From eay@mincom.com Fri Oct 4 18:29:06 1996
337 Received: by orb.mincom.oz.au id AA29080
338 (5.65c/IDA-1.4.4 for eay); Fri, 4 Oct 1996 08:29:07 +1000
339 Date: Fri, 4 Oct 1996 08:29:06 +1000 (EST)
340 From: Eric Young <eay@mincom.oz.au>
342 To: wplatzer <wplatzer@iaik.tu-graz.ac.at>
343 Cc: Eric Young <eay@mincom.oz.au>, SSL Mailing List <ssl-users@mincom.com>
344 Subject: Re: Netscape's Public Key
345 In-Reply-To: <19961003134837.NTM0049@iaik.tu-graz.ac.at>
346 Message-Id: <Pine.SOL.3.91.961004081346.8018K-100000@orb>
348 Content-Type: TEXT/PLAIN; charset=US-ASCII
352 On Thu, 3 Oct 1996, wplatzer wrote:
353 > I get Public Key from Netscape (Gold 3.0b4), but cannot do anything
354 > with it... It looks like (asn1parse):
356 > 0:d=0 hl=3 l=180 cons: SEQUENCE
357 > 3:d=1 hl=2 l= 96 cons: SEQUENCE
358 > 5:d=2 hl=2 l= 92 cons: SEQUENCE
359 > 7:d=3 hl=2 l= 13 cons: SEQUENCE
360 > 9:d=4 hl=2 l= 9 prim: OBJECT :rsaEncryption
361 > 20:d=4 hl=2 l= 0 prim: NULL
362 > 22:d=3 hl=2 l= 75 prim: BIT STRING
363 > 99:d=2 hl=2 l= 0 prim: IA5STRING :
364 > 101:d=1 hl=2 l= 13 cons: SEQUENCE
365 > 103:d=2 hl=2 l= 9 prim: OBJECT :md5withRSAEncryption
366 > 114:d=2 hl=2 l= 0 prim: NULL
367 > 116:d=1 hl=2 l= 65 prim: BIT STRING
369 > The first BIT STRING is the public key and the second BIT STRING is
371 > But a public key consists of the public exponent and the modulus. Are
372 > both numbers in the first BIT STRING?
373 > Is there a document simply describing this coding stuff (checking
374 > signature, get the public key, etc.)?
376 Minimal in SSLeay. If you want to see what the modulus and exponent are,
377 try asn1parse -offset 25 -length 75 <key.pem
378 asn1parse will currently stuff up on the 'length 75' part (fixed in next
379 release) but it will print the stuff. If you are after more
380 documentation on ASN.1, have a look at www.rsa.com and get their PKCS
381 documents, most of my initial work on SSLeay was done using them.
384 util/crypto.num and util/ssl.num are lists of all exported functions in
385 the library (but not macros :-(.
387 The ones for extracting public keys from certificates and certificate
388 requests are EVP_PKEY * X509_REQ_extract_key(X509_REQ *req);
389 EVP_PKEY * X509_extract_key(X509 *x509);
391 To verify a signature on a signed ASN.1 object
392 int X509_verify(X509 *a,EVP_PKEY *key);
393 int X509_REQ_verify(X509_REQ *a,EVP_PKEY *key);
394 int X509_CRL_verify(X509_CRL *a,EVP_PKEY *key);
395 int NETSCAPE_SPKI_verify(NETSCAPE_SPKI *a,EVP_PKEY *key);
397 I should mention that EVP_PKEY can be used to hold a public or a private key,
398 since for things like RSA and DSS, a public key is just a subset of what
399 is stored for the private key.
401 To sign any of the above structures
403 int X509_sign(X509 *a,EVP_PKEY *key,EVP_MD *md);
404 int X509_REQ_sign(X509_REQ *a,EVP_PKEY *key,EVP_MD *md);
405 int X509_CRL_sign(X509_CRL *a,EVP_PKEY *key,EVP_MD *md);
406 int NETSCAPE_SPKI_sign(NETSCAPE_SPKI *a,EVP_PKEY *key,EVP_MD *md);
408 where md is the message digest to sign with.
410 There are all defined in x509.h and all the _sign and _verify functions are
411 actually macros to the ASN1_sign() and ASN1_verify() functions.
412 These functions will put the correct algorithm identifiers in the correct
413 places in the structures.
417 Eric Young | BOOL is tri-state according to Bill Gates.
418 AARNet: eay@mincom.oz.au | RTFM Win32 GetMessage().
420 ==== x509 =======================================================
426 X509_get_serialNumber()
434 X509_set_serialNumber()
441 X509_get_extensions()
442 X509_set_extensions()
444 X509_EXTENSIONS_clear()
445 X509_EXTENSIONS_retrieve()
446 X509_EXTENSIONS_add()
447 X509_EXTENSIONS_delete()
449 ==== x509 attribute ================================================
452 STACK of X509_ATTRIBUTES
461 get_obj_by_nid(STACK , nid)
462 get_num_by_nid(STACK , nid)
463 get_data_by_nid(STACK , nid, index)
465 X509_ATTRIBUTE *X509_ATTRIBUTE_new(void );
466 void X509_ATTRIBUTE_free(X509_ATTRIBUTE *a);
468 X509_ATTRIBUTE *X509_ATTRIBUTE_create_by_NID(X509_ATTRIBUTE **ex,
469 int nid, STACK *value);
471 X509_ATTRIBUTE *X509_ATTRIBUTE_create_by_OBJ(X509_ATTRIBUTE **ex,
472 int nid, STACK *value);
474 int X509_ATTRIBUTE_set_object(X509_ATTRIBUTE *ex,ASN1_OBJECT *obj);
475 int X509_ATTRIBUTE_add_data(X509_ATTRIBUTE *ex, int index,
478 ASN1_OBJECT * X509_ATTRIBUTE_get_object(X509_ATTRIBUTE *ex);
479 int X509_ATTRIBUTE_get_num(X509_ATTRIBUTE *ne);
480 ASN1_TYPE * X509_ATTRIBUTE_get_data(X509_ATTRIBUTE *ne,int index);
482 ASN1_TYPE * X509_ATTRIBUTE_get_data_by_NID(X509_ATTRIBUTE *ne,
485 X509_ATTRIBUTE *PKCS7_get_s_att_by_NID(PKCS7 *p7,int nid);
486 X509_ATTRIBUTE *PKCS7_get_u_att_by_NID(PKCS7 *p7,int nid);
488 ==== x509 v3 ========================================================
492 The X509_EXTENSION_METHOD includes extensions and attributes and/or names.
493 Basically everthing that can be added to an X509 with an OID identifying it.
495 It operates via 2 methods per object id.
496 int a2i_XXX(X509 *x,char *str,int len);
497 int i2a_XXX(BIO *bp,X509 *x);
499 The a2i_XXX function will add the object with a value converted from the
500 string into the X509. Len can be -1 in which case the length is calculated
501 via strlen(str). Applications can always use direct knowledge to load and
502 unload the relevent objects themselves.
504 i2a_XXX will print to the passed BIO, a text representation of the
505 relevet object. Use a memory BIO if you want it printed to a buffer :-).
507 X509_add_by_NID(X509 *x,int nid,char *str,int len);
508 X509_add_by_OBJ(X509 *x,ASN1_OBJECT *obj,char *str,int len);
510 X509_print_by_name(BIO *bp,X509 *x);
511 X509_print_by_NID(BIO *bp,X509 *x);
512 X509_print_by_OBJ(BIO *bp,X509 *x);
514 ==== verify ========================================================
516 X509_verify_cert_chain(
517 CERT_STORE *cert_store,
518 STACK /* X509 */ *certs,
520 int (*verify_error_callback)()
521 char *argument_to_callback, /* SSL */
524 char *app_verify_arg, /* from SSL_CTX */
525 STACK /* X509 */ *certs,
527 int (*verify_error_callback)()
530 int X509_verify_cert(
531 CERT_STORE *cert_store,
534 int (*verify_error_callback)(),
537 ==== apps.doc ========================================================
541 Ok, where to begin....
542 In the begining, when SSLeay was small (April 1995), there
543 were but few applications, they did happily cohabit in
544 the one bin directory. Then over time, they did multiply and grow,
545 and they started to look like microsoft software; 500k to print 'hello world'.
546 A new approach was needed. They were coalessed into one 'Monolithic'
547 application, ssleay. This one program is composed of many programs that
548 can all be compiled independantly.
550 ssleay has 3 modes of operation.
551 1) If the ssleay binaray has the name of one of its component programs, it
552 executes that program and then exits. This can be achieve by using hard or
553 symbolic links, or failing that, just renaming the binary.
554 2) If the first argument to ssleay is the name of one of the component
555 programs, that program runs that program and then exits.
556 3) If there are no arguments, ssleay enters a 'command' mode. Each line is
557 interpreted as a program name plus arguments. After each 'program' is run,
558 ssleay returns to the comand line.
560 dgst - message digests
561 enc - encryption and base64 encoding
563 ans1parse - 'pulls' appart ASN.1 encoded objects like certificates.
565 dh - Diffle-Hellman parameter manipulation.
566 rsa - RSA manipulations.
567 crl - Certificate revokion list manipulations
568 x509 - X509 cert fiddles, including signing.
569 pkcs7 - pkcs7 manipulation, only DER versions right now.
571 genrsa - generate an RSA private key.
572 gendh - Generate a set of Diffle-Hellman parameters.
573 req - Generate a PKCS#10 object, a certificate request.
575 s_client - SSL client program
576 s_server - SSL server program
577 s_time - A SSL protocol timing program
578 s_mult - Another SSL server, but it multiplexes
580 s_filter - under development
582 errstr - Convert SSLeay error numbers to strings.
583 ca - Sign certificate requests, and generate
584 certificate revokion lists
585 crl2pkcs7 - put a crl and certifcates into a pkcs7 object.
586 speed - Benchmark the ciphers.
587 verify - Check certificates
588 hashdir - under development
590 [ there a now a few more options, play with the program to see what they
593 ==== asn1.doc ========================================================
597 ASN.1 is a specification for how to encode structured 'data' in binary form.
598 The approach I have take to the manipulation of structures and their encoding
599 into ASN.1 is as follows.
601 For each distinct structure there are 4 function of the following form
602 TYPE *TYPE_new(void);
603 void TYPE_free(TYPE *);
604 TYPE *d2i_TYPE(TYPE **a,unsigned char **pp,long length);
605 long i2d_TYPE(TYPE *a,unsigned char **pp); /* CHECK RETURN VALUE */
607 where TYPE is the type of the 'object'. The TYPE that have these functions
608 can be in one of 2 forms, either the internal C malloc()ed data structure
609 or in the DER (a variant of ASN.1 encoding) binary encoding which is just
610 an array of unsigned bytes. The 'i2d' functions converts from the internal
611 form to the DER form and the 'd2i' functions convert from the DER form to
614 The 'new' function returns a malloc()ed version of the structure with all
615 substructures either created or left as NULL pointers. For 'optional'
616 fields, they are normally left as NULL to indicate no value. For variable
617 size sub structures (often 'SET OF' or 'SEQUENCE OF' in ASN.1 syntax) the
618 STACK data type is used to hold the values. Have a read of stack.doc
619 and have a look at the relevant header files to see what I mean. If there
620 is an error while malloc()ing the structure, NULL is returned.
622 The 'free' function will free() all the sub components of a particular
623 structure. If any of those sub components have been 'removed', replace
624 them with NULL pointers, the 'free' functions are tolerant of NULL fields.
626 The 'd2i' function copies a binary representation into a C structure. It
627 operates as follows. 'a' is a pointer to a pointer to
628 the structure to populate, 'pp' is a pointer to a pointer to where the DER
629 byte string is located and 'length' is the length of the '*pp' data.
630 If there are no errors, a pointer to the populated structure is returned.
631 If there is an error, NULL is returned. Errors can occur because of
632 malloc() failures but normally they will be due to syntax errors in the DER
633 encoded data being parsed. It is also an error if there was an
634 attempt to read more that 'length' bytes from '*p'. If
635 everything works correctly, the value in '*p' is updated
636 to point at the location just beyond where the DER
637 structure was read from. In this way, chained calls to 'd2i' type
638 functions can be made, with the pointer into the 'data' array being
639 'walked' along the input byte array.
640 Depending on the value passed for 'a', different things will be done. If
641 'a' is NULL, a new structure will be malloc()ed and returned. If '*a' is
642 NULL, a new structure will be malloc()ed and put into '*a' and returned.
643 If '*a' is not NULL, the structure in '*a' will be populated, or in the
644 case of an error, free()ed and then returned.
645 Having these semantics means that a structure
646 can call a 'd2i' function to populate a field and if the field is currently
647 NULL, the structure will be created.
649 The 'i2d' function type is used to copy a C structure to a byte array.
650 The parameter 'a' is the structure to convert and '*p' is where to put it.
651 As for the 'd2i' type structure, 'p' is updated to point after the last
652 byte written. If p is NULL, no data is written. The function also returns
653 the number of bytes written. Where this becomes useful is that if the
654 function is called with a NULL 'p' value, the length is returned. This can
655 then be used to malloc() an array of bytes and then the same function can
656 be recalled passing the malloced array to be written to. e.g.
659 unsigned char *bytes,*p;
660 len=i2d_X509(x,NULL); /* get the size of the ASN1 encoding of 'x' */
661 if ((bytes=(unsigned char *)malloc(len)) == NULL)
666 Please note that a new variable, 'p' was passed to i2d_X509. After the
667 call to i2d_X509 p has been incremented by len bytes.
669 Now the reason for this functional organisation is that it allows nested
670 structures to be built up by calling these functions as required. There
671 are various macros used to help write the general 'i2d', 'd2i', 'new' and
672 'free' functions. They are discussed in another file and would only be
673 used by some-one wanting to add new structures to the library. As you
674 might be able to guess, the process of writing ASN.1 files can be a bit CPU
675 expensive for complex structures. I'm willing to live with this since the
676 simpler library code make my life easier and hopefully most programs using
677 these routines will have their execution profiles dominated by cipher or
678 message digest routines.
679 What follows is a list of 'TYPE' values and the corresponding ASN.1
680 structure and where it is used.
684 ASN1_BIT_STRING BIT STRING
685 ASN1_OCTET_STRING OCTET STRING
686 ASN1_OBJECT OBJECT IDENTIFIER
687 ASN1_PRINTABLESTRING PrintableString
688 ASN1_T61STRING T61String
689 ASN1_IA5STRING IA5String
691 ASN1_TYPE Any of the above mentioned types plus SEQUENCE and SET
693 Most of the above mentioned types are actualled stored in the
694 ASN1_BIT_STRING type and macros are used to differentiate between them.
697 typedef struct asn1_object_st
699 /* both null if a dynamic ASN1_OBJECT, one is
700 * defined if a 'static' ASN1_OBJECT */
706 This is used to store ASN1 OBJECTS. Read 'objects.doc' for details ono
707 routines to manipulate this structure. 'sn' and 'ln' are used to hold text
708 strings that represent the object (short name and long or lower case name).
709 These are used by the 'OBJ' library. 'nid' is a number used by the OBJ
710 library to uniquely identify objects. The ASN1 routines will populate the
711 'length' and 'data' fields which will contain the bit string representing
714 typedef struct asn1_bit_string_st
720 This structure is used to hold all the other base ASN1 types except for
721 ASN1_UTCTIME (which is really just a 'char *'). Length is the number of
722 bytes held in data and type is the ASN1 type of the object (there is a list
725 typedef struct asn1_type_st
730 ASN1_INTEGER * integer;
731 ASN1_BIT_STRING * bit_string;
732 ASN1_OCTET_STRING * octet_string;
733 ASN1_OBJECT * object;
734 ASN1_PRINTABLESTRING * printablestring;
735 ASN1_T61STRING * t61string;
736 ASN1_IA5STRING * ia5string;
737 ASN1_UTCTIME * utctime;
738 ASN1_BIT_STRING * set;
739 ASN1_BIT_STRING * sequence;
742 This structure is used in a few places when 'any' type of object can be
746 X509_CINF CertificateInfo
747 X509_ALGOR AlgorithmIdentifier
749 X509_NAME_ENTRY A single sub component of the name.
751 X509_PUBKEY SubjectPublicKeyInfo
752 The above mentioned types are declared in x509.h. They are all quite
753 straight forward except for the X509_NAME/X509_NAME_ENTRY pair.
754 A X509_NAME is a STACK (see stack.doc) of X509_NAME_ENTRY's.
755 typedef struct X509_name_entry_st
758 ASN1_BIT_STRING *value;
760 int size; /* temp variable */
762 The size is a temporary variable used by i2d_NAME and set is the set number
763 for the particular NAME_ENTRY. A X509_NAME is encoded as a sequence of
764 sequence of sets. Normally each set contains only a single item.
765 Sometimes it contains more. Normally throughout this library there will be
766 only one item per set. The set field contains the 'set' that this entry is
767 a member of. So if you have just created a X509_NAME structure and
768 populated it with X509_NAME_ENTRYs, you should then traverse the X509_NAME
769 (which is just a STACK) and set the 'set/' field to incrementing numbers.
770 For more details on why this is done, read the ASN.1 spec for Distinguished
773 X509_REQ CertificateRequest
774 X509_REQ_INFO CertificateRequestInfo
775 These are used to hold certificate requests.
777 X509_CRL CertificateRevocationList
778 These are used to hold a certificate revocation list
780 RSAPrivateKey PrivateKeyInfo
781 RSAPublicKey PublicKeyInfo
782 Both these 'function groups' operate on 'RSA' structures (see rsa.doc).
783 The difference is that the RSAPublicKey operations only manipulate the m
784 and e fields in the RSA structure.
786 DSAPrivateKey DSS private key
787 DSAPublicKey DSS public key
788 Both these 'function groups' operate on 'DSS' structures (see dsa.doc).
789 The difference is that the RSAPublicKey operations only manipulate the
790 XXX fields in the DSA structure.
793 This is used to hold the p and g value for The Diffie-Hellman operation.
794 The function deal with the 'DH' strucure (see dh.doc).
796 Now all of these function types can be used with several other functions to give
797 quite useful set of general manipulation routines. Normally one would
798 not uses these functions directly but use them via macros.
800 char *ASN1_dup(int (*i2d)(),char *(*d2i)(),char *x);
801 'x' is the input structure case to a 'char *', 'i2d' is the 'i2d_TYPE'
802 function for the type that 'x' is and d2i is the 'd2i_TYPE' function for the
803 type that 'x' is. As is obvious from the parameters, this function
804 duplicates the strucutre by transforming it into the DER form and then
805 re-loading it into a new strucutre and returning the new strucutre. This
806 is obviously a bit cpu intensive but when faced with a complex dynamic
807 structure this is the simplest programming approach. There are macros for
808 duplicating the major data types but is simple to add extras.
810 char *ASN1_d2i_fp(char *(*new)(),char *(*d2i)(),FILE *fp,unsigned char **x);
811 'x' is a pointer to a pointer of the 'desired type'. new and d2i are the
812 corresponding 'TYPE_new' and 'd2i_TYPE' functions for the type and 'fp' is
813 an open file pointer to read from. This function reads from 'fp' as much
814 data as it can and then uses 'd2i' to parse the bytes to load and return
815 the parsed strucutre in 'x' (if it was non-NULL) and to actually return the
816 strucutre. The behavior of 'x' is as per all the other d2i functions.
818 char *ASN1_d2i_bio(char *(*new)(),char *(*d2i)(),BIO *fp,unsigned char **x);
819 The 'BIO' is the new IO type being used in SSLeay (see bio.doc). This
820 function is the same as ASN1_d2i_fp() except for the BIO argument.
821 ASN1_d2i_fp() actually calls this function.
823 int ASN1_i2d_fp(int (*i2d)(),FILE *out,unsigned char *x);
824 'x' is converted to bytes by 'i2d' and then written to 'out'. ASN1_i2d_fp
825 and ASN1_d2i_fp are not really symetric since ASN1_i2d_fp will read all
826 available data from the file pointer before parsing a single item while
827 ASN1_i2d_fp can be used to write a sequence of data objects. To read a
828 series of objects from a file I would sugest loading the file into a buffer
829 and calling the relevent 'd2i' functions.
831 char *ASN1_d2i_bio(char *(*new)(),char *(*d2i)(),BIO *fp,unsigned char **x);
832 This function is the same as ASN1_i2d_fp() except for the BIO argument.
833 ASN1_i2d_fp() actually calls this function.
835 char * PEM_ASN1_read(char *(*d2i)(),char *name,FILE *fp,char **x,int (*cb)());
836 This function will read the next PEM encoded (base64) object of the same
837 type as 'x' (loaded by the d2i function). 'name' is the name that is in
838 the '-----BEGIN name-----' that designates the start of that object type.
839 If the data is encrypted, 'cb' will be called to prompt for a password. If
840 it is NULL a default function will be used to prompt from the password.
841 'x' is delt with as per the standard 'd2i' function interface. This
842 function can be used to read a series of objects from a file. While any
843 data type can be encrypted (see PEM_ASN1_write) only RSA private keys tend
846 char * PEM_ASN1_read_bio(char *(*d2i)(),char *name,BIO *fp,
847 char **x,int (*cb)());
848 Same as PEM_ASN1_read() except using a BIO. This is called by
851 int PEM_ASN1_write(int (*i2d)(),char *name,FILE *fp,char *x,EVP_CIPHER *enc,
852 unsigned char *kstr,int klen,int (*callback)());
854 int PEM_ASN1_write_bio(int (*i2d)(),char *name,BIO *fp,
855 char *x,EVP_CIPHER *enc,unsigned char *kstr,int klen,
858 int ASN1_sign(int (*i2d)(), X509_ALGOR *algor1, X509_ALGOR *algor2,
859 ASN1_BIT_STRING *signature, char *data, RSA *rsa, EVP_MD *type);
860 int ASN1_verify(int (*i2d)(), X509_ALGOR *algor1,
861 ASN1_BIT_STRING *signature,char *data, RSA *rsa);
863 int ASN1_BIT_STRING_cmp(ASN1_BIT_STRING *a, ASN1_BIT_STRING *b);
864 ASN1_BIT_STRING *ASN1_BIT_STRING_type_new(int type );
866 int ASN1_UTCTIME_check(ASN1_UTCTIME *a);
867 void ASN1_UTCTIME_print(BIO *fp,ASN1_UTCTIME *a);
868 ASN1_UTCTIME *ASN1_UTCTIME_dup(ASN1_UTCTIME *a);
870 ASN1_BIT_STRING *d2i_asn1_print_type(ASN1_BIT_STRING **a,unsigned char **pp,
871 long length,int type);
873 int i2d_ASN1_SET(STACK *a, unsigned char **pp,
874 int (*func)(), int ex_tag, int ex_class);
875 STACK * d2i_ASN1_SET(STACK **a, unsigned char **pp, long length,
876 char *(*func)(), int ex_tag, int ex_class);
878 int i2a_ASN1_OBJECT(BIO *bp,ASN1_OBJECT *object);
879 int i2a_ASN1_INTEGER(BIO *bp, ASN1_INTEGER *a);
880 int a2i_ASN1_INTEGER(BIO *bp,ASN1_INTEGER *bs,char *buf,int size);
882 int ASN1_INTEGER_set(ASN1_INTEGER *a, long v);
883 long ASN1_INTEGER_get(ASN1_INTEGER *a);
884 ASN1_INTEGER *BN_to_ASN1_INTEGER(BIGNUM *bn, ASN1_INTEGER *ai);
885 BIGNUM *ASN1_INTEGER_to_BN(ASN1_INTEGER *ai,BIGNUM *bn);
887 /* given a string, return the correct type. Max is the maximum number
888 * of bytes to parse. It stops parsing when 'max' bytes have been
889 * processed or a '\0' is hit */
890 int ASN1_PRINTABLE_type(unsigned char *s,int max);
892 void ASN1_parse(BIO *fp,unsigned char *pp,long len);
894 int i2d_ASN1_bytes(ASN1_BIT_STRING *a, unsigned char **pp, int tag, int class);
895 ASN1_BIT_STRING *d2i_ASN1_bytes(ASN1_OCTET_STRING **a, unsigned char **pp,
896 long length, int Ptag, int Pclass);
899 int asn1_Finish(ASN1_CTX *c);
902 int ASN1_get_object(unsigned char **pp, long *plength, int *ptag,
903 int *pclass, long omax);
904 int ASN1_check_infinite_end(unsigned char **p,long len);
905 void ASN1_put_object(unsigned char **pp, int constructed, int length,
907 int ASN1_object_size(int constructed, int length, int tag);
909 X509 * X509_get_cert(CERTIFICATE_CTX *ctx,X509_NAME * name,X509 *tmp_x509);
910 int X509_add_cert(CERTIFICATE_CTX *ctx,X509 *);
912 char * X509_cert_verify_error_string(int n);
913 int X509_add_cert_file(CERTIFICATE_CTX *c,char *file, int type);
914 char * X509_gmtime (char *s, long adj);
915 int X509_add_cert_dir (CERTIFICATE_CTX *c,char *dir, int type);
916 int X509_load_verify_locations (CERTIFICATE_CTX *ctx,
917 char *file_env, char *dir_env);
918 int X509_set_default_verify_paths(CERTIFICATE_CTX *cts);
919 X509 * X509_new_D2i_X509(int len, unsigned char *p);
920 char * X509_get_default_cert_area(void );
921 char * X509_get_default_cert_dir(void );
922 char * X509_get_default_cert_file(void );
923 char * X509_get_default_cert_dir_env(void );
924 char * X509_get_default_cert_file_env(void );
925 char * X509_get_default_private_dir(void );
926 X509_REQ *X509_X509_TO_req(X509 *x, RSA *rsa);
927 int X509_cert_verify(CERTIFICATE_CTX *ctx,X509 *xs, int (*cb)());
929 CERTIFICATE_CTX *CERTIFICATE_CTX_new();
930 void CERTIFICATE_CTX_free(CERTIFICATE_CTX *c);
932 void X509_NAME_print(BIO *fp, X509_NAME *name, int obase);
933 int X509_print_fp(FILE *fp,X509 *x);
934 int X509_print(BIO *fp,X509 *x);
936 X509_INFO * X509_INFO_new(void);
937 void X509_INFO_free(X509_INFO *a);
939 char * X509_NAME_oneline(X509_NAME *a);
941 #define X509_verify(x,rsa)
942 #define X509_REQ_verify(x,rsa)
943 #define X509_CRL_verify(x,rsa)
945 #define X509_sign(x,rsa,md)
946 #define X509_REQ_sign(x,rsa,md)
947 #define X509_CRL_sign(x,rsa,md)
949 #define X509_dup(x509)
950 #define d2i_X509_fp(fp,x509)
951 #define i2d_X509_fp(fp,x509)
952 #define d2i_X509_bio(bp,x509)
953 #define i2d_X509_bio(bp,x509)
955 #define X509_CRL_dup(crl)
956 #define d2i_X509_CRL_fp(fp,crl)
957 #define i2d_X509_CRL_fp(fp,crl)
958 #define d2i_X509_CRL_bio(bp,crl)
959 #define i2d_X509_CRL_bio(bp,crl)
961 #define X509_REQ_dup(req)
962 #define d2i_X509_REQ_fp(fp,req)
963 #define i2d_X509_REQ_fp(fp,req)
964 #define d2i_X509_REQ_bio(bp,req)
965 #define i2d_X509_REQ_bio(bp,req)
967 #define RSAPrivateKey_dup(rsa)
968 #define d2i_RSAPrivateKey_fp(fp,rsa)
969 #define i2d_RSAPrivateKey_fp(fp,rsa)
970 #define d2i_RSAPrivateKey_bio(bp,rsa)
971 #define i2d_RSAPrivateKey_bio(bp,rsa)
973 #define X509_NAME_dup(xn)
974 #define X509_NAME_ENTRY_dup(ne)
976 void X509_REQ_print_fp(FILE *fp,X509_REQ *req);
977 void X509_REQ_print(BIO *fp,X509_REQ *req);
979 RSA *X509_REQ_extract_key(X509_REQ *req);
980 RSA *X509_extract_key(X509 *x509);
982 int X509_issuer_and_serial_cmp(X509 *a, X509 *b);
983 unsigned long X509_issuer_and_serial_hash(X509 *a);
985 X509_NAME * X509_get_issuer_name(X509 *a);
986 int X509_issuer_name_cmp(X509 *a, X509 *b);
987 unsigned long X509_issuer_name_hash(X509 *a);
989 X509_NAME * X509_get_subject_name(X509 *a);
990 int X509_subject_name_cmp(X509 *a,X509 *b);
991 unsigned long X509_subject_name_hash(X509 *x);
993 int X509_NAME_cmp (X509_NAME *a, X509_NAME *b);
994 unsigned long X509_NAME_hash(X509_NAME *x);
997 ==== bio.doc ========================================================
1001 This documentation is rather sparse, you are probably best
1002 off looking at the code for specific details.
1004 The BIO library is a IO abstraction that was originally
1005 inspired by the need to have callbacks to perform IO to FILE
1006 pointers when using Windows 3.1 DLLs. There are two types
1007 of BIO; a source/sink type and a filter type.
1008 The source/sink methods are as follows:
1009 - BIO_s_mem() memory buffer - a read/write byte array that
1010 grows until memory runs out :-).
1011 - BIO_s_file() FILE pointer - A wrapper around the normal
1012 'FILE *' commands, good for use with stdin/stdout.
1013 - BIO_s_fd() File descriptor - A wrapper around file
1014 descriptors, often used with pipes.
1015 - BIO_s_socket() Socket - Used around sockets. It is
1016 mostly in the Microsoft world that sockets are different
1017 from file descriptors and there are all those ugly winsock
1019 - BIO_s_null() Null - read nothing and write nothing.; a
1020 useful endpoint for filter type BIO's specifically things
1021 like the message digest BIO.
1023 The filter types are
1024 - BIO_f_buffer() IO buffering - does output buffering into
1025 larger chunks and performs input buffering to allow gets()
1027 - BIO_f_md() Message digest - a transparent filter that can
1028 be asked to return a message digest for the data that has
1030 - BIO_f_cipher() Encrypt or decrypt all data passing
1032 - BIO_f_base64() Base64 decode on read and encode on write.
1033 - BIO_f_ssl() A filter that performs SSL encryption on the
1034 data sent through it.
1037 The BIO library has a set of base functions that are
1038 implemented for each particular type. Filter BIOs will
1039 normally call the equivalent function on the source/sink BIO
1040 that they are layered on top of after they have performed
1041 some modification to the data stream. Multiple filter BIOs
1042 can be 'push' into a stack of modifers, so to read from a
1043 file, unbase64 it, then decrypt it, a BIO_f_cipher,
1044 BIO_f_base64 and a BIO_s_file would probably be used. If a
1045 sha-1 and md5 message digest needed to be generated, a stack
1046 two BIO_f_md() BIOs and a BIO_s_null() BIO could be used.
1047 The base functions are
1048 - BIO *BIO_new(BIO_METHOD *type); Create a new BIO of type 'type'.
1049 - int BIO_free(BIO *a); Free a BIO structure. Depending on
1050 the configuration, this will free the underlying data
1051 object for a source/sink BIO.
1052 - int BIO_read(BIO *b, char *data, int len); Read upto 'len'
1054 - int BIO_gets(BIO *bp,char *buf, int size); Depending on
1055 the BIO, this can either be a 'get special' or a get one
1056 line of data, as per fgets();
1057 - int BIO_write(BIO *b, char *data, int len); Write 'len'
1058 bytes from 'data' to the 'b' BIO.
1059 - int BIO_puts(BIO *bp,char *buf); Either a 'put special' or
1060 a write null terminated string as per fputs().
1061 - long BIO_ctrl(BIO *bp,int cmd,long larg,char *parg); A
1062 control function which is used to manipulate the BIO
1063 structure and modify it's state and or report on it. This
1064 function is just about never used directly, rather it
1065 should be used in conjunction with BIO_METHOD specific
1067 - BIO *BIO_push(BIO *new_top, BIO *old); new_top is apped to the
1068 top of the 'old' BIO list. new_top should be a filter BIO.
1069 All writes will go through 'new_top' first and last on read.
1071 - BIO *BIO_pop(BIO *bio); the new topmost BIO is returned, NULL if
1074 If a particular low level BIO method is not supported
1075 (normally BIO_gets()), -2 will be returned if that method is
1076 called. Otherwise the IO methods (read, write, gets, puts)
1077 will return the number of bytes read or written, and 0 or -1
1078 for error (or end of input). For the -1 case,
1079 BIO_should_retry(bio) can be called to determine if it was a
1080 genuine error or a temporary problem. -2 will also be
1081 returned if the BIO has not been initalised yet, in all
1082 cases, the correct error codes are set (accessible via the
1086 The following functions are convenience functions:
1087 - int BIO_printf(BIO *bio, char * format, ..); printf but
1089 - long BIO_ctrl_int(BIO *bp,int cmd,long larg,int iarg); a
1090 convenience function to allow a different argument types
1091 to be passed to BIO_ctrl().
1092 - int BIO_dump(BIO *b,char *bytes,int len); output 'len'
1093 bytes from 'bytes' in a hex dump debug format.
1094 - long BIO_debug_callback(BIO *bio, int cmd, char *argp, int
1095 argi, long argl, long ret) - a default debug BIO callback,
1096 this is mentioned below. To use this one normally has to
1097 use the BIO_set_callback_arg() function to assign an
1098 output BIO for the callback to use.
1099 - BIO *BIO_find_type(BIO *bio,int type); when there is a 'stack'
1100 of BIOs, this function scan the list and returns the first
1101 that is of type 'type', as listed in buffer.h under BIO_TYPE_XXX.
1102 - void BIO_free_all(BIO *bio); Free the bio and all other BIOs
1103 in the list. It walks the bio->next_bio list.
1107 Extra commands are normally implemented as macros calling BIO_ctrl().
1108 - BIO_number_read(BIO *bio) - the number of bytes processed
1110 - BIO_number_written(BIO *bio) - the number of bytes written
1111 by BIO_write(bio,.).
1112 - BIO_reset(BIO *bio) - 'reset' the BIO.
1113 - BIO_eof(BIO *bio) - non zero if we are at the current end
1115 - BIO_set_close(BIO *bio, int close_flag) - set the close flag.
1116 - BIO_get_close(BIO *bio) - return the close flag.
1117 BIO_pending(BIO *bio) - return the number of bytes waiting
1118 to be read (normally buffered internally).
1119 - BIO_flush(BIO *bio) - output any data waiting to be output.
1120 - BIO_should_retry(BIO *io) - after a BIO_read/BIO_write
1121 operation returns 0 or -1, a call to this function will
1122 return non zero if you should retry the call later (this
1123 is for non-blocking IO).
1124 - BIO_should_read(BIO *io) - we should retry when data can
1126 - BIO_should_write(BIO *io) - we should retry when data can
1128 - BIO_method_name(BIO *io) - return a string for the method name.
1129 - BIO_method_type(BIO *io) - return the unique ID of the BIO method.
1130 - BIO_set_callback(BIO *io, long (*callback)(BIO *io, int
1131 cmd, char *argp, int argi, long argl, long ret); - sets
1133 - BIO_get_callback(BIO *io) - return the assigned function
1135 - BIO_set_callback_arg(BIO *io, char *arg) - assign some
1136 data against the BIO. This is normally used by the debug
1137 callback but could in reality be used for anything. To
1138 get an idea of how all this works, have a look at the code
1139 in the default debug callback mentioned above. The
1140 callback can modify the return values.
1142 Details of the BIO_METHOD structure.
1143 typedef struct bio_method_st
1156 The 'type' is the numeric type of the BIO, these are listed in buffer.h;
1157 'Name' is a textual representation of the BIO 'type'.
1158 The 7 function pointers point to the respective function
1159 methods, some of which can be NULL if not implemented.
1161 typedef struct bio_st
1164 long (*callback)(BIO * bio, int mode, char *argp, int
1165 argi, long argl, long ret);
1166 char *cb_arg; /* first argument for the callback */
1169 int flags; /* extra storage */
1172 struct bio_st *next_bio; /* used by filter BIOs */
1174 unsigned long num_read;
1175 unsigned long num_write;
1178 - 'Method' is the BIO method.
1179 - 'callback', when configured, is called before and after
1180 each BIO method is called for that particular BIO. This
1181 is intended primarily for debugging and of informational feedback.
1182 - 'init' is 0 when the BIO can be used for operation.
1183 Often, after a BIO is created, a number of operations may
1184 need to be performed before it is available for use. An
1185 example is for BIO_s_sock(). A socket needs to be
1186 assigned to the BIO before it can be used.
1187 - 'shutdown', this flag indicates if the underlying
1188 comunication primative being used should be closed/freed
1189 when the BIO is closed.
1190 - 'flags' is used to hold extra state. It is primarily used
1191 to hold information about why a non-blocking operation
1192 failed and to record startup protocol information for the
1194 - 'num' and 'ptr' are used to hold instance specific state
1195 like file descriptors or local data structures.
1196 - 'next_bio' is used by filter BIOs to hold the pointer of the
1197 next BIO in the chain. written data is sent to this BIO and
1198 data read is taken from it.
1199 - 'references' is used to indicate the number of pointers to
1200 this structure. This needs to be '1' before a call to
1201 BIO_free() is made if the BIO_free() function is to
1202 actually free() the structure, otherwise the reference
1203 count is just decreased. The actual BIO subsystem does
1204 not really use this functionality but it is useful when
1205 used in more advanced applicaion.
1206 - num_read and num_write are the total number of bytes
1207 read/written via the 'read()' and 'write()' methods.
1209 BIO_ctrl operations.
1210 The following is the list of standard commands passed as the
1211 second parameter to BIO_ctrl() and should be supported by
1212 all BIO as best as possible. Some are optional, some are
1213 manditory, in any case, where is makes sense, a filter BIO
1214 should pass such requests to underlying BIO's.
1215 - BIO_CTRL_RESET - Reset the BIO back to an initial state.
1216 - BIO_CTRL_EOF - return 0 if we are not at the end of input,
1218 - BIO_CTRL_INFO - BIO specific special command, normal
1220 - BIO_CTRL_SET - set IO specific parameter.
1221 - BIO_CTRL_GET - get IO specific parameter.
1222 - BIO_CTRL_GET_CLOSE - Get the close on BIO_free() flag, one
1223 of BIO_CLOSE or BIO_NOCLOSE.
1224 - BIO_CTRL_SET_CLOSE - Set the close on BIO_free() flag.
1225 - BIO_CTRL_PENDING - Return the number of bytes available
1227 - BIO_CTRL_FLUSH - Output pending data, return number of bytes output.
1228 - BIO_CTRL_SHOULD_RETRY - After an IO error (-1 returned)
1229 should we 'retry' when IO is possible on the underlying IO object.
1230 - BIO_CTRL_RETRY_TYPE - What kind of IO are we waiting on.
1232 The following command is a special BIO_s_file() specific option.
1233 - BIO_CTRL_SET_FILENAME - specify a file to open for IO.
1235 The BIO_CTRL_RETRY_TYPE needs a little more explanation.
1236 When performing non-blocking IO, or say reading on a memory
1237 BIO, when no data is present (or cannot be written),
1238 BIO_read() and/or BIO_write() will return -1.
1239 BIO_should_retry(bio) will return true if this is due to an
1240 IO condition rather than an actual error. In the case of
1241 BIO_s_mem(), a read when there is no data will return -1 and
1242 a should retry when there is more 'read' data.
1243 The retry type is deduced from 2 macros
1244 BIO_should_read(bio) and BIO_should_write(bio).
1245 Now while it may appear obvious that a BIO_read() failure
1246 should indicate that a retry should be performed when more
1247 read data is available, this is often not true when using
1248 things like an SSL BIO. During the SSL protocol startup
1249 multiple reads and writes are performed, triggered by any
1250 SSL_read or SSL_write.
1251 So to write code that will transparently handle either a
1256 if (BIO_should_retry(bio))
1258 if (BIO_should_read(bio))
1260 /* call us again when BIO can be read */
1262 if (BIO_should_write(bio))
1264 /* call us again when BIO can be written */
1269 At this point in time only read and write conditions can be
1270 used but in the future I can see the situation for other
1271 conditions, specifically with SSL there could be a condition
1272 of a X509 certificate lookup taking place and so the non-
1273 blocking BIO_read would require a retry when the certificate
1274 lookup subsystem has finished it's lookup. This is all
1275 makes more sense and is easy to use in a event loop type
1277 When using the SSL BIO, either SSL_read() or SSL_write()s
1278 can be called during the protocol startup and things will
1279 still work correctly.
1280 The nice aspect of the use of the BIO_should_retry() macro
1281 is that all the errno codes that indicate a non-fatal error
1282 are encapsulated in one place. The Windows specific error
1283 codes and WSAGetLastError() calls are also hidden from the
1286 Notes on each BIO method.
1287 Normally buffer.h is just required but depending on the
1288 BIO_METHOD, ssl.h or evp.h will also be required.
1290 BIO_METHOD *BIO_s_mem(void);
1291 - BIO_set_mem_buf(BIO *bio, BUF_MEM *bm, int close_flag) -
1292 set the underlying BUF_MEM structure for the BIO to use.
1293 - BIO_get_mem_ptr(BIO *bio, char **pp) - if pp is not NULL,
1294 set it to point to the memory array and return the number
1296 A read/write BIO. Any data written is appended to the
1297 memory array and any read is read from the front. This BIO
1298 can be used for read/write at the same time. BIO_gets() is
1299 supported in the fgets() sense.
1300 BIO_CTRL_INFO can be used to retrieve pointers to the memory
1301 buffer and it's length.
1303 BIO_METHOD *BIO_s_file(void);
1304 - BIO_set_fp(BIO *bio, FILE *fp, int close_flag) - set 'FILE *' to use.
1305 - BIO_get_fp(BIO *bio, FILE **fp) - get the 'FILE *' in use.
1306 - BIO_read_filename(BIO *bio, char *name) - read from file.
1307 - BIO_write_filename(BIO *bio, char *name) - write to file.
1308 - BIO_append_filename(BIO *bio, char *name) - append to file.
1309 This BIO sits over the normal system fread()/fgets() type
1310 functions. Gets() is supported. This BIO in theory could be
1311 used for read and write but it is best to think of each BIO
1312 of this type as either a read or a write BIO, not both.
1314 BIO_METHOD *BIO_s_socket(void);
1315 BIO_METHOD *BIO_s_fd(void);
1316 - BIO_sock_should_retry(int i) - the underlying function
1317 used to determine if a call should be retried; the
1318 argument is the '0' or '-1' returned by the previous BIO
1320 - BIO_fd_should_retry(int i) - same as the
1321 - BIO_sock_should_retry() except that it is different internally.
1322 - BIO_set_fd(BIO *bio, int fd, int close_flag) - set the
1323 file descriptor to use
1324 - BIO_get_fd(BIO *bio, int *fd) - get the file descriptor.
1325 These two methods are very similar. Gets() is not
1326 supported, if you want this functionality, put a
1327 BIO_f_buffer() onto it. This BIO is bi-directional if the
1328 underlying file descriptor is. This is normally the case
1329 for sockets but not the case for stdio descriptors.
1331 BIO_METHOD *BIO_s_null(void);
1332 Read and write as much data as you like, it all disappears
1335 BIO_METHOD *BIO_f_buffer(void);
1336 - BIO_get_buffer_num_lines(BIO *bio) - return the number of
1337 complete lines in the buffer.
1338 - BIO_set_buffer_size(BIO *bio, long size) - set the size of
1340 This type performs input and output buffering. It performs
1341 both at the same time. The size of the buffer can be set
1342 via the set buffer size option. Data buffered for output is
1343 only written when the buffer fills.
1345 BIO_METHOD *BIO_f_ssl(void);
1346 - BIO_set_ssl(BIO *bio, SSL *ssl, int close_flag) - the SSL
1348 - BIO_get_ssl(BIO *bio, SSL **ssl) - get the SSL structure
1350 The SSL bio is a little different from normal BIOs because
1351 the underlying SSL structure is a little different. A SSL
1352 structure performs IO via a read and write BIO. These can
1353 be different and are normally set via the
1354 SSL_set_rbio()/SSL_set_wbio() calls. The SSL_set_fd() calls
1355 are just wrappers that create socket BIOs and then call
1356 SSL_set_bio() where the read and write BIOs are the same.
1357 The BIO_push() operation makes the SSLs IO BIOs the same, so
1358 make sure the BIO pushed is capable of two directional
1359 traffic. If it is not, you will have to install the BIOs
1360 via the more conventional SSL_set_bio() call. BIO_pop() will retrieve
1363 BIO_METHOD *BIO_f_md(void);
1364 - BIO_set_md(BIO *bio, EVP_MD *md) - set the message digest
1366 - BIO_get_md(BIO *bio, EVP_MD **mdp) - return the digest
1367 method in use in mdp, return 0 if not set yet.
1368 - BIO_reset() reinitializes the digest (EVP_DigestInit())
1369 and passes the reset to the underlying BIOs.
1370 All data read or written via BIO_read() or BIO_write() to
1371 this BIO will be added to the calculated digest. This
1372 implies that this BIO is only one directional. If read and
1373 write operations are performed, two separate BIO_f_md() BIOs
1374 are reuqired to generate digests on both the input and the
1375 output. BIO_gets(BIO *bio, char *md, int size) will place the
1376 generated digest into 'md' and return the number of bytes.
1377 The EVP_MAX_MD_SIZE should probably be used to size the 'md'
1378 array. Reading the digest will also reset it.
1380 BIO_METHOD *BIO_f_cipher(void);
1381 - BIO_reset() reinitializes the cipher.
1382 - BIO_flush() should be called when the last bytes have been
1383 output to flush the final block of block ciphers.
1384 - BIO_get_cipher_status(BIO *b), when called after the last
1385 read from a cipher BIO, returns non-zero if the data
1386 decrypted correctly, otherwise, 0.
1387 - BIO_set_cipher(BIO *b, EVP_CIPHER *c, unsigned char *key,
1388 unsigned char *iv, int encrypt) This function is used to
1389 setup a cipher BIO. The length of key and iv are
1390 specified by the choice of EVP_CIPHER. Encrypt is 1 to
1391 encrypt and 0 to decrypt.
1393 BIO_METHOD *BIO_f_base64(void);
1394 - BIO_flush() should be called when the last bytes have been output.
1395 This BIO base64 encodes when writing and base64 decodes when
1396 reading. It will scan the input until a suitable begin line
1397 is found. After reading data, BIO_reset() will reset the
1398 BIO to start scanning again. Do not mix reading and writing
1399 on the same base64 BIO. It is meant as a single stream BIO.
1403 one/both BIO_s_file()
1413 It is easy to mix one and two directional BIOs, all one has
1414 to do is to keep two separate BIO pointers for reading and
1415 writing and be careful about usage of underlying BIOs. The
1416 SSL bio by it's very nature has to be two directional but
1417 the BIO_push() command will push the one BIO into the SSL
1418 BIO for both reading and writing.
1420 The best example program to look at is apps/enc.c and/or perhaps apps/dgst.c.
1423 ==== blowfish.doc ========================================================
1425 The Blowfish library.
1427 Blowfish is a block cipher that operates on 64bit (8 byte) quantities. It
1428 uses variable size key, but 128bit (16 byte) key would normally be considered
1429 good. It can be used in all the modes that DES can be used. This
1430 library implements the ecb, cbc, cfb64, ofb64 modes.
1432 Blowfish is quite a bit faster that DES, and much faster than IDEA or
1433 RC2. It is one of the faster block ciphers.
1435 For all calls that have an 'input' and 'output' variables, they can be the
1438 This library requires the inclusion of 'blowfish.h'.
1440 All of the encryption functions take what is called an BF_KEY as an
1441 argument. An BF_KEY is an expanded form of the Blowfish key.
1442 For all modes of the Blowfish algorithm, the BF_KEY used for
1443 decryption is the same one that was used for encryption.
1445 The define BF_ENCRYPT is passed to specify encryption for the functions
1446 that require an encryption/decryption flag. BF_DECRYPT is passed to
1449 Please note that any of the encryption modes specified in my DES library
1450 could be used with Blowfish. I have only implemented ecb, cbc, cfb64 and
1451 ofb64 for the following reasons.
1452 - ecb is the basic Blowfish encryption.
1453 - cbc is the normal 'chaining' form for block ciphers.
1454 - cfb64 can be used to encrypt single characters, therefore input and output
1455 do not need to be a multiple of 8.
1456 - ofb64 is similar to cfb64 but is more like a stream cipher, not as
1457 secure (not cipher feedback) but it does not have an encrypt/decrypt mode.
1458 - If you want triple Blowfish, thats 384 bits of key and you must be totally
1459 obsessed with security. Still, if you want it, it is simple enough to
1460 copy the function from the DES library and change the des_encrypt to
1461 BF_encrypt; an exercise left for the paranoid reader :-).
1463 The functions are as follows:
1469 BF_set_key converts an 'len' byte key into a BF_KEY.
1470 A 'ks' is an expanded form of the 'key' which is used to
1471 perform actual encryption. It can be regenerated from the Blowfish key
1472 so it only needs to be kept when encryption or decryption is about
1473 to occur. Don't save or pass around BF_KEY's since they
1474 are CPU architecture dependent, 'key's are not. Blowfish is an
1475 interesting cipher in that it can be used with a variable length
1476 key. 'len' is the length of 'key' to be used as the key.
1477 A 'len' of 16 is recomended by me, but blowfish can use upto
1478 72 bytes. As a warning, blowfish has a very very slow set_key
1479 function, it actually runs BF_encrypt 521 times.
1481 void BF_encrypt(unsigned long *data, BF_KEY *key);
1482 void BF_decrypt(unsigned long *data, BF_KEY *key);
1483 These are the Blowfish encryption function that gets called by just
1484 about every other Blowfish routine in the library. You should not
1485 use this function except to implement 'modes' of Blowfish.
1486 I say this because the
1487 functions that call this routine do the conversion from 'char *' to
1488 long, and this needs to be done to make sure 'non-aligned' memory
1489 access do not occur.
1490 Data is a pointer to 2 unsigned long's and key is the
1493 void BF_ecb_encrypt(
1498 This is the basic Electronic Code Book form of Blowfish (in DES this
1499 mode is called Electronic Code Book so I'm going to use the term
1500 for blowfish as well.
1501 Input is encrypted into output using the key represented by
1502 key. Depending on the encrypt, encryption or
1503 decryption occurs. Input is 8 bytes long and output is 8 bytes.
1505 void BF_cbc_encrypt(
1510 unsigned char *ivec,
1512 This routine implements Blowfish in Cipher Block Chaining mode.
1513 Input, which should be a multiple of 8 bytes is encrypted
1514 (or decrypted) to output which will also be a multiple of 8 bytes.
1515 The number of bytes is in length (and from what I've said above,
1516 should be a multiple of 8). If length is not a multiple of 8, bad
1517 things will probably happen. ivec is the initialisation vector.
1518 This function updates iv after each call so that it can be passed to
1519 the next call to BF_cbc_encrypt().
1521 void BF_cfb64_encrypt(
1526 unsigned char *ivec,
1529 This is one of the more useful functions in this Blowfish library, it
1530 implements CFB mode of Blowfish with 64bit feedback.
1531 This allows you to encrypt an arbitrary number of bytes,
1532 you do not require 8 byte padding. Each call to this
1533 routine will encrypt the input bytes to output and then update ivec
1534 and num. Num contains 'how far' we are though ivec.
1535 'Encrypt' is used to indicate encryption or decryption.
1536 CFB64 mode operates by using the cipher to generate a stream
1537 of bytes which is used to encrypt the plain text.
1538 The cipher text is then encrypted to generate the next 64 bits to
1539 be xored (incrementally) with the next 64 bits of plain
1540 text. As can be seen from this, to encrypt or decrypt,
1541 the same 'cipher stream' needs to be generated but the way the next
1542 block of data is gathered for encryption is different for
1543 encryption and decryption.
1545 void BF_ofb64_encrypt(
1550 unsigned char *ivec,
1552 This functions implements OFB mode of Blowfish with 64bit feedback.
1553 This allows you to encrypt an arbitrary number of bytes,
1554 you do not require 8 byte padding. Each call to this
1555 routine will encrypt the input bytes to output and then update ivec
1556 and num. Num contains 'how far' we are though ivec.
1557 This is in effect a stream cipher, there is no encryption or
1560 For reading passwords, I suggest using des_read_pw_string() from my DES library.
1561 To generate a password from a text string, I suggest using MD5 (or MD2) to
1562 produce a 16 byte message digest that can then be passed directly to
1566 For more information about the specific Blowfish modes in this library
1567 (ecb, cbc, cfb and ofb), read the section entitled 'Modes of DES' from the
1568 documentation on my DES library. What is said about DES is directly
1569 applicable for Blowfish.
1572 ==== bn.doc ========================================================
1574 The Big Number library.
1576 #include "bn.h" when using this library.
1578 This big number library was written for use in implementing the RSA and DH
1579 public key encryption algorithms. As such, features such as negative
1580 numbers have not been extensively tested but they should work as expected.
1581 This library uses dynamic memory allocation for storing its data structures
1582 and so there are no limit on the size of the numbers manipulated by these
1583 routines but there is always the requirement to check return codes from
1584 functions just in case a memory allocation error has occurred.
1586 The basic object in this library is a BIGNUM. It is used to hold a single
1587 large integer. This type should be considered opaque and fields should not
1588 be modified or accessed directly.
1589 typedef struct bignum_st
1591 int top; /* Index of last used d. */
1592 BN_ULONG *d; /* Pointer to an array of 'BITS2' bit chunks. */
1593 int max; /* Size of the d array. */
1596 The big number is stored in a malloced array of BN_ULONG's. A BN_ULONG can
1597 be either 16, 32 or 64 bits in size, depending on the 'number of bits'
1599 The 'd' field is this array. 'max' is the size of the 'd' array that has
1600 been allocated. 'top' is the 'last' entry being used, so for a value of 4,
1601 bn.d[0]=4 and bn.top=1. 'neg' is 1 if the number is negative.
1602 When a BIGNUM is '0', the 'd' field can be NULL and top == 0.
1604 Various routines in this library require the use of 'temporary' BIGNUM
1605 variables during their execution. Due to the use of dynamic memory
1606 allocation to create BIGNUMs being rather expensive when used in
1607 conjunction with repeated subroutine calls, the BN_CTX structure is
1608 used. This structure contains BN_CTX BIGNUMs. BN_CTX
1609 is the maximum number of temporary BIGNUMs any publicly exported
1613 typedef struct bignum_ctx
1615 int tos; /* top of stack */
1616 BIGNUM *bn[BN_CTX]; /* The variables */
1619 The functions that follow have been grouped according to function. Most
1620 arithmetic functions return a result in the first argument, sometimes this
1621 first argument can also be an input parameter, sometimes it cannot. These
1622 restrictions are documented.
1624 extern BIGNUM *BN_value_one;
1625 There is one variable defined by this library, a BIGNUM which contains the
1626 number 1. This variable is useful for use in comparisons and assignment.
1630 int BN_num_bits(BIGNUM *a);
1631 This function returns the size of 'a' in bits.
1633 int BN_num_bytes(BIGNUM *a);
1634 This function (macro) returns the size of 'a' in bytes.
1635 For conversion of BIGNUMs to byte streams, this is the number of
1636 bytes the output string will occupy. If the output byte
1637 format specifies that the 'top' bit indicates if the number is
1638 signed, so an extra '0' byte is required if the top bit on a
1639 positive number is being written, it is upto the application to
1640 make this adjustment. Like I said at the start, I don't
1641 really support negative numbers :-).
1643 Creation/Destruction routines.
1646 Return a new BIGNUM object. The number initially has a value of 0. If
1647 there is an error, NULL is returned.
1649 void BN_free(BIGNUM *a);
1652 void BN_clear(BIGNUM *a);
1653 Sets 'a' to a value of 0 and also zeros all unused allocated
1654 memory. This function is used to clear a variable of 'sensitive'
1655 data that was held in it.
1657 void BN_clear_free(BIGNUM *a);
1658 This function zeros the memory used by 'a' and then free()'s it.
1659 This function should be used to BN_free() BIGNUMS that have held
1660 sensitive numeric values like RSA private key values. Both this
1661 function and BN_clear tend to only be used by RSA and DH routines.
1663 BN_CTX *BN_CTX_new(void);
1664 Returns a new BN_CTX. NULL on error.
1666 void BN_CTX_free(BN_CTX *c);
1667 Free a BN_CTX structure. The BIGNUMs in 'c' are BN_clear_free()ed.
1669 BIGNUM *bn_expand(BIGNUM *b, int bits);
1670 This is an internal function that should not normally be used. It
1671 ensures that 'b' has enough room for a 'bits' bit number. It is
1672 mostly used by the various BIGNUM routines. If there is an error,
1673 NULL is returned. if not, 'b' is returned.
1675 BIGNUM *BN_copy(BIGNUM *to, BIGNUM *from);
1676 The 'from' is copied into 'to'. NULL is returned if there is an
1677 error, otherwise 'to' is returned.
1679 BIGNUM *BN_dup(BIGNUM *a);
1680 A new BIGNUM is created and returned containing the value of 'a'.
1681 NULL is returned on error.
1683 Comparison and Test Functions.
1685 int BN_is_zero(BIGNUM *a)
1686 Return 1 if 'a' is zero, else 0.
1689 Return 1 is 'a' is one, else 0.
1692 Return 1 if 'a' == w, else 0. 'w' is a BN_ULONG.
1694 int BN_cmp(BIGNUM *a, BIGNUM *b);
1695 Return -1 if 'a' is less than 'b', 0 if 'a' and 'b' are the same
1696 and 1 is 'a' is greater than 'b'. This is a signed comparison.
1698 int BN_ucmp(BIGNUM *a, BIGNUM *b);
1699 This function is the same as BN_cmp except that the comparison
1700 ignores the sign of the numbers.
1702 Arithmetic Functions
1703 For all of these functions, 0 is returned if there is an error and 1 is
1704 returned for success. The return value should always be checked. eg.
1705 if (!BN_add(r,a,b)) goto err;
1706 Unless explicitly mentioned, the 'return' value can be one of the
1707 'parameters' to the function.
1709 int BN_add(BIGNUM *r, BIGNUM *a, BIGNUM *b);
1710 Add 'a' and 'b' and return the result in 'r'. This is r=a+b.
1712 int BN_sub(BIGNUM *r, BIGNUM *a, BIGNUM *b);
1713 Subtract 'a' from 'b' and put the result in 'r'. This is r=a-b.
1715 int BN_lshift(BIGNUM *r, BIGNUM *a, int n);
1716 Shift 'a' left by 'n' bits. This is r=a*(2^n).
1718 int BN_lshift1(BIGNUM *r, BIGNUM *a);
1719 Shift 'a' left by 1 bit. This form is more efficient than
1720 BN_lshift(r,a,1). This is r=a*2.
1722 int BN_rshift(BIGNUM *r, BIGNUM *a, int n);
1723 Shift 'a' right by 'n' bits. This is r=int(a/(2^n)).
1725 int BN_rshift1(BIGNUM *r, BIGNUM *a);
1726 Shift 'a' right by 1 bit. This form is more efficient than
1727 BN_rshift(r,a,1). This is r=int(a/2).
1729 int BN_mul(BIGNUM *r, BIGNUM *a, BIGNUM *b);
1730 Multiply a by b and return the result in 'r'. 'r' must not be
1731 either 'a' or 'b'. It has to be a different BIGNUM.
1734 int BN_sqr(BIGNUM *r, BIGNUM *a, BN_CTX *ctx);
1735 Multiply a by a and return the result in 'r'. 'r' must not be
1736 'a'. This function is alot faster than BN_mul(r,a,a). This is r=a*a.
1738 int BN_div(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BIGNUM *d, BN_CTX *ctx);
1739 Divide 'm' by 'd' and return the result in 'dv' and the remainder
1740 in 'rem'. Either of 'dv' or 'rem' can be NULL in which case that
1741 value is not returned. 'ctx' needs to be passed as a source of
1742 temporary BIGNUM variables.
1743 This is dv=int(m/d), rem=m%d.
1745 int BN_mod(BIGNUM *rem, BIGNUM *m, BIGNUM *d, BN_CTX *ctx);
1746 Find the remainder of 'm' divided by 'd' and return it in 'rem'.
1747 'ctx' holds the temporary BIGNUMs required by this function.
1748 This function is more efficient than BN_div(NULL,rem,m,d,ctx);
1751 int BN_mod_mul(BIGNUM *r, BIGNUM *a, BIGNUM *b, BIGNUM *m,BN_CTX *ctx);
1752 Multiply 'a' by 'b' and return the remainder when divided by 'm'.
1753 'ctx' holds the temporary BIGNUMs required by this function.
1756 int BN_mod_exp(BIGNUM *r, BIGNUM *a, BIGNUM *p, BIGNUM *m,BN_CTX *ctx);
1757 Raise 'a' to the 'p' power and return the remainder when divided by
1758 'm'. 'ctx' holds the temporary BIGNUMs required by this function.
1761 int BN_reciprocal(BIGNUM *r, BIGNUM *m, BN_CTX *ctx);
1762 Return the reciprocal of 'm'. 'ctx' holds the temporary variables
1763 required. This function returns -1 on error, otherwise it returns
1764 the number of bits 'r' is shifted left to make 'r' into an integer.
1765 This number of bits shifted is required in BN_mod_mul_reciprocal().
1766 This is r=(1/m)<<(BN_num_bits(m)+1).
1768 int BN_mod_mul_reciprocal(BIGNUM *r, BIGNUM *x, BIGNUM *y, BIGNUM *m,
1769 BIGNUM *i, int nb, BN_CTX *ctx);
1770 This function is used to perform an efficient BN_mod_mul()
1771 operation. If one is going to repeatedly perform BN_mod_mul() with
1772 the same modulus is worth calculating the reciprocal of the modulus
1773 and then using this function. This operation uses the fact that
1774 a/b == a*r where r is the reciprocal of b. On modern computers
1775 multiplication is very fast and big number division is very slow.
1776 'x' is multiplied by 'y' and then divided by 'm' and the remainder
1777 is returned. 'i' is the reciprocal of 'm' and 'nb' is the number
1778 of bits as returned from BN_reciprocal(). Normal usage is as follows.
1779 bn=BN_reciprocal(i,m);
1781 { BN_mod_mul_reciprocal(r,x,y,m,i,bn,ctx); }
1782 This is r=(x*y)%m. Internally it is approximately
1783 r=(x*y)-m*(x*y/m) or r=(x*y)-m*((x*y*i) >> bn)
1784 This function is used in BN_mod_exp() and BN_is_prime().
1786 Assignment Operations
1788 int BN_one(BIGNUM *a)
1789 Set 'a' to hold the value one.
1792 int BN_zero(BIGNUM *a)
1793 Set 'a' to hold the value zero.
1796 int BN_set_word(BIGNUM *a, unsigned long w);
1797 Set 'a' to hold the value of 'w'. 'w' is an unsigned long.
1800 unsigned long BN_get_word(BIGNUM *a);
1801 Returns 'a' in an unsigned long. Not remarkably, often 'a' will
1802 be biger than a word, in which case 0xffffffffL is returned.
1805 These functions are much more efficient that the normal bignum arithmetic
1808 BN_ULONG BN_mod_word(BIGNUM *a, unsigned long w);
1809 Return the remainder of 'a' divided by 'w'.
1810 This is return(a%w).
1812 int BN_add_word(BIGNUM *a, unsigned long w);
1813 Add 'w' to 'a'. This function does not take the sign of 'a' into
1814 account. This is a+=w;
1818 int BN_is_bit_set(BIGNUM *a, int n);
1819 This function return 1 if bit 'n' is set in 'a' else 0.
1821 int BN_set_bit(BIGNUM *a, int n);
1822 This function sets bit 'n' to 1 in 'a'.
1823 This is a&= ~(1<<n);
1825 int BN_clear_bit(BIGNUM *a, int n);
1826 This function sets bit 'n' to zero in 'a'. Return 0 if less
1827 than 'n' bits in 'a' else 1. This is a&= ~(1<<n);
1829 int BN_mask_bits(BIGNUM *a, int n);
1830 Truncate 'a' to n bits long. This is a&= ~((~0)<<n)
1832 Format conversion routines.
1834 BIGNUM *BN_bin2bn(unsigned char *s, int len,BIGNUM *ret);
1835 This function converts 'len' bytes in 's' into a BIGNUM which
1836 is put in 'ret'. If ret is NULL, a new BIGNUM is created.
1837 Either this new BIGNUM or ret is returned. The number is
1838 assumed to be in bigendian form in 's'. By this I mean that
1839 to 'ret' is created as follows for 'len' == 5.
1840 ret = s[0]*2^32 + s[1]*2^24 + s[2]*2^16 + s[3]*2^8 + s[4];
1841 This function cannot be used to convert negative numbers. It
1842 is always assumed the number is positive. The application
1843 needs to diddle the 'neg' field of th BIGNUM its self.
1844 The better solution would be to save the numbers in ASN.1 format
1845 since this is a defined standard for storing big numbers.
1846 Look at the functions
1848 ASN1_INTEGER *BN_to_ASN1_INTEGER(BIGNUM *bn, ASN1_INTEGER *ai);
1849 BIGNUM *ASN1_INTEGER_to_BN(ASN1_INTEGER *ai,BIGNUM *bn);
1850 int i2d_ASN1_INTEGER(ASN1_INTEGER *a,unsigned char **pp);
1851 ASN1_INTEGER *d2i_ASN1_INTEGER(ASN1_INTEGER **a,unsigned char **pp,
1854 int BN_bn2bin(BIGNUM *a, unsigned char *to);
1855 This function converts 'a' to a byte string which is put into
1856 'to'. The representation is big-endian in that the most
1857 significant byte of 'a' is put into to[0]. This function
1858 returns the number of bytes used to hold 'a'. BN_num_bytes(a)
1859 would return the same value and can be used to determine how
1860 large 'to' needs to be. If the number is negative, this
1861 information is lost. Since this library was written to
1862 manipulate large positive integers, the inability to save and
1863 restore them is not considered to be a problem by me :-).
1864 As for BN_bin2bn(), look at the ASN.1 integer encoding funtions
1865 for SSLeay. They use BN_bin2bn() and BN_bn2bin() internally.
1867 char *BN_bn2ascii(BIGNUM *a);
1868 This function returns a malloc()ed string that contains the
1869 ascii hexadecimal encoding of 'a'. The number is in bigendian
1870 format with a '-' in front if the number is negative.
1872 int BN_ascii2bn(BIGNUM **bn, char *a);
1873 The inverse of BN_bn2ascii. The function returns the number of
1874 characters from 'a' were processed in generating a the bignum.
1875 error is inticated by 0 being returned. The number is a
1876 hex digit string, optionally with a leading '-'. If *bn
1877 is null, a BIGNUM is created and returned via that variable.
1879 int BN_print_fp(FILE *fp, BIGNUM *a);
1880 'a' is printed to file pointer 'fp'. It is in the same format
1881 that is output from BN_bn2ascii(). 0 is returned on error,
1884 int BN_print(BIO *bp, BIGNUM *a);
1885 Same as BN_print except that the output is done to the SSLeay libraries
1886 BIO routines. BN_print_fp() actually calls this function.
1888 Miscellaneous Routines.
1890 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
1891 This function returns in 'rnd' a random BIGNUM that is bits
1892 long. If bottom is 1, the number returned is odd. If top is set,
1893 the top 2 bits of the number are set. This is useful because if
1894 this is set, 2 'n; bit numbers multiplied together will return a 2n
1895 bit number. If top was not set, they could produce a 2n-1 bit
1898 BIGNUM *BN_mod_inverse(BIGNUM *a, BIGNUM *n,BN_CTX *ctx);
1899 This function create a new BIGNUM and returns it. This number
1900 is the inverse mod 'n' of 'a'. By this it is meant that the
1901 returned value 'r' satisfies (a*r)%n == 1. This function is
1902 used in the generation of RSA keys. 'ctx', as per usual,
1903 is used to hold temporary variables that are required by the
1904 function. NULL is returned on error.
1906 int BN_gcd(BIGNUM *r,BIGNUM *a,BIGNUM *b,BN_CTX *ctx);
1907 'r' has the greatest common divisor of 'a' and 'b'. 'ctx' is
1908 used for temporary variables and 0 is returned on error.
1910 int BN_is_prime(BIGNUM *p,int nchecks,void (*callback)(),BN_CTX *ctx,
1912 This function is used to check if a BIGNUM ('p') is prime.
1913 It performs this test by using the Miller-Rabin randomised
1914 primality test. This is a probalistic test that requires a
1915 number of rounds to ensure the number is prime to a high
1916 degree of probability. Since this can take quite some time, a
1917 callback function can be passed and it will be called each
1918 time 'p' passes a round of the prime testing. 'callback' will
1919 be called as follows, callback(1,n,cb_arg) where n is the number of
1920 the round, just passed. As per usual 'ctx' contains temporary
1921 variables used. If ctx is NULL, it does not matter, a local version
1922 will be malloced. This parameter is present to save some mallocing
1923 inside the function but probably could be removed.
1924 0 is returned on error.
1925 'ncheck' is the number of Miller-Rabin tests to run. It is
1926 suggested to use the value 'BN_prime_checks' by default.
1928 BIGNUM *BN_generate_prime(
1933 void (*callback)());
1935 This function is used to generate prime numbers. It returns a
1936 new BIGNUM that has a high probability of being a prime.
1937 'bits' is the number of bits that
1938 are to be in the prime. If 'strong' is true, the returned prime
1939 will also be a strong prime ((p-1)/2 is also prime).
1940 While searching for the prime ('p'), we
1941 can add the requirement that the prime fill the following
1942 condition p%a == rem. This can be used to help search for
1943 primes with specific features, which is required when looking
1944 for primes suitable for use with certain 'g' values in the
1945 Diffie-Hellman key exchange algorithm. If 'a' is NULL,
1946 this condition is not checked. If rem is NULL, rem is assumed
1947 to be 1. Since this search for a prime
1948 can take quite some time, if callback is not NULL, it is called
1949 in the following situations.
1950 We have a suspected prime (from a quick sieve),
1951 callback(0,sus_prime++,cb_arg). Each item to be passed to BN_is_prime().
1952 callback(1,round++,cb_arg). Each successful 'round' in BN_is_prime().
1953 callback(2,round,cb_arg). For each successful BN_is_prime() test.
1958 DSA wants 64*32 to use word mont mul, but RSA wants to use full.
1960 ==== callback.doc ========================================================
1962 Callback functions used in SSLeay.
1964 --------------------------
1967 Each BIO structure can have a callback defined against it. This callback is
1968 called 2 times for each BIO 'function'. It is passed 6 parameters.
1969 BIO_debug_callback() is an example callback which is defined in
1970 crypto/buffer/bio_cb.c and is used in apps/dgst.c This is intended mostly
1971 for debuging or to notify the application of IO.
1973 long BIO_debug_callback(BIO *bio,int cmd,char *argp,int argi,long argl,
1975 bio is the BIO being called, cmd is the type of BIO function being called.
1976 Look at the BIO_CB_* defines in buffer.h. Argp and argi are the arguments
1977 passed to BIO_read(), BIO_write, BIO_gets(), BIO_puts(). In the case of
1978 BIO_ctrl(), argl is also defined. The first time the callback is called,
1979 before the underlying function has been executed, 0 is passed as 'ret', and
1980 if the return code from the callback is not > 0, the call is aborted
1981 and the returned <= 0 value is returned.
1982 The second time the callback is called, the 'cmd' value also has
1983 BIO_CB_RETURN logically 'or'ed with it. The 'ret' value is the value returned
1984 from the actuall function call and whatever the callback returns is returned
1985 from the BIO function.
1987 BIO_set_callback(b,cb) can be used to set the callback function
1988 (b is a BIO), and BIO_set_callback_arg(b,arg) can be used to
1989 set the cb_arg argument in the BIO strucutre. This field is only intended
1990 to be used by application, primarily in the callback function since it is
1991 accessable since the BIO is passed.
1993 --------------------------
1996 The pem library only really uses one type of callback,
1997 static int def_callback(char *buf, int num, int verify);
1998 which is used to return a password string if required.
1999 'buf' is the buffer to put the string in. 'num' is the size of 'buf'
2000 and 'verify' is used to indicate that the password should be checked.
2001 This last flag is mostly used when reading a password for encryption.
2003 For all of these functions, a NULL callback will call the above mentioned
2004 default callback. This default function does not work under Windows 3.1.
2005 For other machines, it will use an application defined prompt string
2006 (EVP_set_pw_prompt(), which defines a library wide prompt string)
2007 if defined, otherwise it will use it's own PEM password prompt.
2008 It will then call EVP_read_pw_string() to get a password from the console.
2009 If your application wishes to use nice fancy windows to retrieve passwords,
2010 replace this function. The callback should return the number of bytes read
2011 into 'buf'. If the number of bytes <= 0, it is considered an error.
2013 Functions that take this callback are listed below. For the 'read' type
2014 functions, the callback will only be required if the PEM data is encrypted.
2016 For the Write functions, normally a password can be passed in 'kstr', of
2017 'klen' bytes which will be used if the 'enc' cipher is not NULL. If
2018 'kstr' is NULL, the callback will be used to retrieve a password.
2020 int PEM_do_header (EVP_CIPHER_INFO *cipher, unsigned char *data,long *len,
2022 char *PEM_ASN1_read_bio(char *(*d2i)(),char *name,BIO *bp,char **x,int (*cb)());
2023 char *PEM_ASN1_read(char *(*d2i)(),char *name,FILE *fp,char **x,int (*cb)());
2024 int PEM_ASN1_write_bio(int (*i2d)(),char *name,BIO *bp,char *x,
2025 EVP_CIPHER *enc,unsigned char *kstr,int klen,int (*callback)());
2026 int PEM_ASN1_write(int (*i2d)(),char *name,FILE *fp,char *x,
2027 EVP_CIPHER *enc,unsigned char *kstr,int klen,int (*callback)());
2028 STACK *PEM_X509_INFO_read(FILE *fp, STACK *sk, int (*cb)());
2029 STACK *PEM_X509_INFO_read_bio(BIO *fp, STACK *sk, int (*cb)());
2031 #define PEM_write_RSAPrivateKey(fp,x,enc,kstr,klen,cb)
2032 #define PEM_write_DSAPrivateKey(fp,x,enc,kstr,klen,cb)
2033 #define PEM_write_bio_RSAPrivateKey(bp,x,enc,kstr,klen,cb)
2034 #define PEM_write_bio_DSAPrivateKey(bp,x,enc,kstr,klen,cb)
2035 #define PEM_read_SSL_SESSION(fp,x,cb)
2036 #define PEM_read_X509(fp,x,cb)
2037 #define PEM_read_X509_REQ(fp,x,cb)
2038 #define PEM_read_X509_CRL(fp,x,cb)
2039 #define PEM_read_RSAPrivateKey(fp,x,cb)
2040 #define PEM_read_DSAPrivateKey(fp,x,cb)
2041 #define PEM_read_PrivateKey(fp,x,cb)
2042 #define PEM_read_PKCS7(fp,x,cb)
2043 #define PEM_read_DHparams(fp,x,cb)
2044 #define PEM_read_bio_SSL_SESSION(bp,x,cb)
2045 #define PEM_read_bio_X509(bp,x,cb)
2046 #define PEM_read_bio_X509_REQ(bp,x,cb)
2047 #define PEM_read_bio_X509_CRL(bp,x,cb)
2048 #define PEM_read_bio_RSAPrivateKey(bp,x,cb)
2049 #define PEM_read_bio_DSAPrivateKey(bp,x,cb)
2050 #define PEM_read_bio_PrivateKey(bp,x,cb)
2051 #define PEM_read_bio_PKCS7(bp,x,cb)
2052 #define PEM_read_bio_DHparams(bp,x,cb)
2053 int i2d_Netscape_RSA(RSA *a, unsigned char **pp, int (*cb)());
2054 RSA *d2i_Netscape_RSA(RSA **a, unsigned char **pp, long length, int (*cb)());
2056 Now you will notice that macros like
2057 #define PEM_write_X509(fp,x) \
2058 PEM_ASN1_write((int (*)())i2d_X509,PEM_STRING_X509,fp, \
2059 (char *)x, NULL,NULL,0,NULL)
2060 Don't do encryption normally. If you want to PEM encrypt your X509 structure,
2061 either just call PEM_ASN1_write directly or just define you own
2062 macro variant. As you can see, this macro just sets all encryption related
2066 --------------------------
2069 #define SSL_set_info_callback(ssl,cb)
2070 #define SSL_CTX_set_info_callback(ctx,cb)
2071 void callback(SSL *ssl,int location,int ret)
2072 This callback is called each time around the SSL_connect()/SSL_accept()
2073 state machine. So it will be called each time the SSL protocol progresses.
2074 It is mostly present for use when debugging. When SSL_connect() or
2075 SSL_accept() return, the location flag is SSL_CB_ACCEPT_EXIT or
2076 SSL_CB_CONNECT_EXIT and 'ret' is the value about to be returned.
2077 Have a look at the SSL_CB_* defines in ssl.h. If an info callback is defined
2078 against the SSL_CTX, it is called unless there is one set against the SSL.
2080 void client_info_callback() in apps/s_client() for an example.
2082 Certificate verification.
2083 void SSL_set_verify(SSL *s, int mode, int (*callback) ());
2084 void SSL_CTX_set_verify(SSL_CTX *ctx,int mode,int (*callback)());
2085 This callback is used to help verify client and server X509 certificates.
2086 It is actually passed to X509_cert_verify(), along with the SSL structure
2087 so you have to read about X509_cert_verify() :-). The SSL_CTX version is used
2088 if the SSL version is not defined. X509_cert_verify() is the function used
2089 by the SSL part of the library to verify certificates. This function is
2090 nearly always defined by the application.
2092 void SSL_CTX_set_cert_verify_cb(SSL_CTX *ctx, int (*cb)(),char *arg);
2093 int callback(char *arg,SSL *s,X509 *xs,STACK *cert_chain);
2094 This call is used to replace the SSLeay certificate verification code.
2095 The 'arg' is kept in the SSL_CTX and is passed to the callback.
2096 If the callback returns 0, the certificate is rejected, otherwise it
2097 is accepted. The callback is replacing the X509_cert_verify() call.
2098 This feature is not often used, but if you wished to implement
2099 some totally different certificate authentication system, this 'hook' is
2102 SSLeay keeps a cache of session-ids against each SSL_CTX. These callbacks can
2103 be used to notify the application when a SSL_SESSION is added to the cache
2104 or to retrieve a SSL_SESSION that is not in the cache from the application.
2105 #define SSL_CTX_sess_set_get_cb(ctx,cb)
2106 SSL_SESSION *callback(SSL *s,char *session_id,int session_id_len,int *copy);
2107 If defined, this callback is called to return the SESSION_ID for the
2108 session-id in 'session_id', of 'session_id_len' bytes. 'copy' is set to 1
2109 if the server is to 'take a copy' of the SSL_SESSION structure. It is 0
2110 if the SSL_SESSION is being 'passed in' so the SSLeay library is now
2111 responsible for 'free()ing' the structure. Basically it is used to indicate
2112 if the reference count on the SSL_SESSION structure needs to be incremented.
2114 #define SSL_CTX_sess_set_new_cb(ctx,cb)
2115 int callback(SSL *s, SSL_SESSION *sess);
2116 When a new connection is established, if the SSL_SESSION is going to be added
2117 to the cache, this callback is called. Return 1 if a 'copy' is required,
2118 otherwise, return 0. This return value just causes the reference count
2119 to be incremented (on return of a 1), this means the application does
2120 not need to worry about incrementing the refernece count (and the
2121 locking that implies in a multi-threaded application).
2123 void SSL_CTX_set_default_passwd_cb(SSL_CTX *ctx,int (*cb)());
2124 This sets the SSL password reading function.
2125 It is mostly used for windowing applications
2126 and used by PEM_read_bio_X509() and PEM_read_bio_RSAPrivateKey()
2127 calls inside the SSL library. The only reason this is present is because the
2128 calls to PEM_* functions is hidden in the SSLeay library so you have to
2129 pass in the callback some how.
2131 #define SSL_CTX_set_client_cert_cb(ctx,cb)
2132 int callback(SSL *s,X509 **x509, EVP_PKEY **pkey);
2133 Called when a client certificate is requested but there is not one set
2134 against the SSL_CTX or the SSL. If the callback returns 1, x509 and
2135 pkey need to point to valid data. The library will free these when
2136 required so if the application wants to keep these around, increment
2137 their reference counts. If 0 is returned, no client cert is
2138 available. If -1 is returned, it is assumed that the callback needs
2139 to be called again at a later point in time. SSL_connect will return
2140 -1 and SSL_want_x509_lookup(ssl) returns true. Remember that
2141 application data can be attached to an SSL structure via the
2142 SSL_set_app_data(SSL *ssl,char *data) call.
2144 --------------------------
2147 int X509_cert_verify(CERTIFICATE_CTX *ctx,X509 *xs, int (*cb)(),
2148 int *error,char *arg,STACK *cert_chain);
2149 int verify_callback(int ok,X509 *xs,X509 *xi,int depth,int error,char *arg,
2152 X509_cert_verify() is used to authenticate X509 certificates. The 'ctx' holds
2153 the details of the various caches and files used to locate certificates.
2154 'xs' is the certificate to verify and 'cb' is the application callback (more
2155 detail later). 'error' will be set to the error code and 'arg' is passed
2156 to the 'cb' callback. Look at the VERIFY_* defines in crypto/x509/x509.h
2158 When ever X509_cert_verify() makes a 'negative' decision about a
2159 certitificate, the callback is called. If everything checks out, the
2160 callback is called with 'VERIFY_OK' or 'VERIFY_ROOT_OK' (for a self
2161 signed cert that is not the passed certificate).
2163 The callback is passed the X509_cert_verify opinion of the certificate
2164 in 'ok', the certificate in 'xs', the issuer certificate in 'xi',
2165 the 'depth' of the certificate in the verification 'chain', the
2166 VERIFY_* code in 'error' and the argument passed to X509_cert_verify()
2167 in 'arg'. cert_chain is a list of extra certs to use if they are not
2170 The callback can be used to look at the error reason, and then return 0
2171 for an 'error' or '1' for ok. This will override the X509_cert_verify()
2172 opinion of the certificates validity. Processing will continue depending on
2173 the return value. If one just wishes to use the callback for informational
2174 reason, just return the 'ok' parameter.
2176 --------------------------
2177 The BN and DH library.
2179 BIGNUM *BN_generate_prime(int bits,int strong,BIGNUM *add,
2180 BIGNUM *rem,void (*callback)(int,int));
2181 int BN_is_prime(BIGNUM *p,int nchecks,void (*callback)(int,int),
2183 Read doc/bn.doc for the description of these 2.
2185 DH *DH_generate_parameters(int prime_len,int generator,
2186 void (*callback)(int,int));
2187 Read doc/bn.doc for the description of the callback, since it is just passed
2188 to BN_generate_prime(), except that it is also called as
2189 callback(3,0) by this function.
2191 --------------------------
2194 void CRYPTO_set_locking_callback(void (*func)(int mode,int type,char *file,
2196 void CRYPTO_set_add_lock_callback(int (*func)(int *num,int mount,
2197 int type,char *file, int line));
2198 void CRYPTO_set_id_callback(unsigned long (*func)(void));
2200 Read threads.doc for info on these ones.
2203 ==== cipher.doc ========================================================
2205 The Cipher subroutines.
2207 These routines require "evp.h" to be included.
2209 These functions are a higher level interface to the various cipher
2210 routines found in this library. As such, they allow the same code to be
2211 used to encrypt and decrypt via different ciphers with only a change
2212 in an initial parameter. These routines also provide buffering for block
2215 These routines all take a pointer to the following structure to specify
2216 which cipher to use. If you wish to use a new cipher with these routines,
2217 you would probably be best off looking an how an existing cipher is
2218 implemented and copying it. At this point in time, I'm not going to go
2219 into many details. This structure should be considered opaque
2221 typedef struct pem_cipher_st
2227 void (*enc_init)(); /* init for encryption */
2228 void (*dec_init)(); /* init for decryption */
2229 void (*do_cipher)(); /* encrypt data */
2232 The type field is the object NID of the cipher type
2233 (read the section on Objects for an explanation of what a NID is).
2234 The cipher block_size is how many bytes need to be passed
2235 to the cipher at a time. Key_len is the
2236 length of the key the cipher requires and iv_len is the length of the
2237 initialisation vector required. enc_init is the function
2238 called to initialise the ciphers context for encryption and dec_init is the
2239 function to initialise for decryption (they need to be different, especially
2240 for the IDEA cipher).
2242 One reason for specifying the Cipher via a pointer to a structure
2243 is that if you only use des-cbc, only the des-cbc routines will
2244 be included when you link the program. If you passed an integer
2245 that specified which cipher to use, the routine that mapped that
2246 integer to a set of cipher functions would cause all the ciphers
2247 to be link into the code. This setup also allows new ciphers
2248 to be added by the application (with some restrictions).
2250 The thirteen ciphers currently defined in this library are
2252 EVP_CIPHER *EVP_des_ecb(); /* DES in ecb mode, iv=0, block=8, key= 8 */
2253 EVP_CIPHER *EVP_des_ede(); /* DES in ecb ede mode, iv=0, block=8, key=16 */
2254 EVP_CIPHER *EVP_des_ede3(); /* DES in ecb ede mode, iv=0, block=8, key=24 */
2255 EVP_CIPHER *EVP_des_cfb(); /* DES in cfb mode, iv=8, block=1, key= 8 */
2256 EVP_CIPHER *EVP_des_ede_cfb(); /* DES in ede cfb mode, iv=8, block=1, key=16 */
2257 EVP_CIPHER *EVP_des_ede3_cfb();/* DES in ede cfb mode, iv=8, block=1, key=24 */
2258 EVP_CIPHER *EVP_des_ofb(); /* DES in ofb mode, iv=8, block=1, key= 8 */
2259 EVP_CIPHER *EVP_des_ede_ofb(); /* DES in ede ofb mode, iv=8, block=1, key=16 */
2260 EVP_CIPHER *EVP_des_ede3_ofb();/* DES in ede ofb mode, iv=8, block=1, key=24 */
2261 EVP_CIPHER *EVP_des_cbc(); /* DES in cbc mode, iv=8, block=8, key= 8 */
2262 EVP_CIPHER *EVP_des_ede_cbc(); /* DES in cbc ede mode, iv=8, block=8, key=16 */
2263 EVP_CIPHER *EVP_des_ede3_cbc();/* DES in cbc ede mode, iv=8, block=8, key=24 */
2264 EVP_CIPHER *EVP_desx_cbc(); /* DES in desx cbc mode,iv=8, block=8, key=24 */
2265 EVP_CIPHER *EVP_rc4(); /* RC4, iv=0, block=1, key=16 */
2266 EVP_CIPHER *EVP_idea_ecb(); /* IDEA in ecb mode, iv=0, block=8, key=16 */
2267 EVP_CIPHER *EVP_idea_cfb(); /* IDEA in cfb mode, iv=8, block=1, key=16 */
2268 EVP_CIPHER *EVP_idea_ofb(); /* IDEA in ofb mode, iv=8, block=1, key=16 */
2269 EVP_CIPHER *EVP_idea_cbc(); /* IDEA in cbc mode, iv=8, block=8, key=16 */
2270 EVP_CIPHER *EVP_rc2_ecb(); /* RC2 in ecb mode, iv=0, block=8, key=16 */
2271 EVP_CIPHER *EVP_rc2_cfb(); /* RC2 in cfb mode, iv=8, block=1, key=16 */
2272 EVP_CIPHER *EVP_rc2_ofb(); /* RC2 in ofb mode, iv=8, block=1, key=16 */
2273 EVP_CIPHER *EVP_rc2_cbc(); /* RC2 in cbc mode, iv=8, block=8, key=16 */
2274 EVP_CIPHER *EVP_bf_ecb(); /* Blowfish in ecb mode,iv=0, block=8, key=16 */
2275 EVP_CIPHER *EVP_bf_cfb(); /* Blowfish in cfb mode,iv=8, block=1, key=16 */
2276 EVP_CIPHER *EVP_bf_ofb(); /* Blowfish in ofb mode,iv=8, block=1, key=16 */
2277 EVP_CIPHER *EVP_bf_cbc(); /* Blowfish in cbc mode,iv=8, block=8, key=16 */
2279 The meaning of the compound names is as follows.
2280 des The base cipher is DES.
2281 idea The base cipher is IDEA
2282 rc4 The base cipher is RC4-128
2283 rc2 The base cipher is RC2-128
2284 ecb Electronic Code Book form of the cipher.
2285 cbc Cipher Block Chaining form of the cipher.
2286 cfb 64 bit Cipher Feedback form of the cipher.
2287 ofb 64 bit Output Feedback form of the cipher.
2288 ede The cipher is used in Encrypt, Decrypt, Encrypt mode. The first
2289 and last keys are the same.
2290 ede3 The cipher is used in Encrypt, Decrypt, Encrypt mode.
2292 All the Cipher routines take a EVP_CIPHER_CTX pointer as an argument.
2293 The state of the cipher is kept in this structure.
2295 typedef struct EVP_CIPHER_Ctx_st
2298 int encrypt; /* encrypt or decrypt */
2299 int buf_len; /* number we have left */
2300 unsigned char buf[8];
2302 .... /* cipher specific stuff */
2306 Cipher is a pointer the the EVP_CIPHER for the current context. The encrypt
2307 flag indicates encryption or decryption. buf_len is the number of bytes
2308 currently being held in buf.
2309 The 'c' union holds the cipher specify context.
2311 The following functions are to be used.
2313 int EVP_read_pw_string(
2318 This function is the same as des_read_pw_string() (des.doc).
2320 void EVP_set_pw_prompt(char *prompt);
2321 This function sets the 'default' prompt to use to use in
2322 EVP_read_pw_string when the prompt parameter is NULL. If the
2323 prompt parameter is NULL, this 'default prompt' feature is turned
2324 off. Be warned, this is a global variable so weird things
2325 will happen if it is used under Win16 and care must be taken
2326 with a multi-threaded version of the library.
2328 char *EVP_get_pw_prompt();
2329 This returns a pointer to the default prompt string. NULL
2335 unsigned char *salt,
2336 unsigned char *data,
2341 This function is used to generate a key and an initialisation vector
2342 for a specified cipher from a key string and a salt. Type
2343 specifies the cipher the 'key' is being generated for. Md is the
2344 message digest algorithm to use to generate the key and iv. The salt
2345 is an optional 8 byte object that is used to help seed the key
2347 If the salt value is NULL, it is just not used. Datal is the
2348 number of bytes to use from 'data' in the key generation.
2349 This function returns the key size for the specified cipher, if
2350 data is NULL, this value is returns and no other
2351 computation is performed. Count is
2352 the number of times to loop around the key generator. I would
2353 suggest leaving it's value as 1. Key and iv are the structures to
2354 place the returning iv and key in. If they are NULL, no value is
2355 generated for that particular value.
2356 The algorithm used is as follows
2358 /* M[] is an array of message digests
2359 * MD() is the message digest function */
2360 M[0]=MD(data . salt);
2361 for (i=1; i<count; i++) M[0]=MD(M[0]);
2364 while (data still needed for key and iv)
2366 M[i]=MD(M[i-1] . data . salt);
2367 for (i=1; i<count; i++) M[i]=MD(M[i]);
2371 If the salt is NULL, it is not used.
2372 The digests are concatenated together.
2373 M = M[0] . M[1] . M[2] .......
2375 For key= 8, iv=8 => key=M[0.. 8], iv=M[ 9 .. 16].
2376 For key=16, iv=0 => key=M[0..16].
2377 For key=16, iv=8 => key=M[0..16], iv=M[17 .. 24].
2378 For key=24, iv=8 => key=M[0..24], iv=M[25 .. 32].
2380 This routine will produce DES-CBC keys and iv that are compatible
2381 with the PKCS-5 standard when md2 or md5 are used. If md5 is
2382 used, the salt is NULL and count is 1, this routine will produce
2383 the password to key mapping normally used with RC4.
2384 I have attempted to logically extend the PKCS-5 standard to
2385 generate keys and iv for ciphers that require more than 16 bytes,
2386 if anyone knows what the correct standard is, please inform me.
2387 When using sha or sha1, things are a bit different under this scheme,
2388 since sha produces a 20 byte digest. So for ciphers requiring
2389 24 bits of data, 20 will come from the first MD and 4 will
2390 come from the second.
2392 I have considered having a separate function so this 'routine'
2393 can be used without the requirement of passing a EVP_CIPHER *,
2394 but I have decided to not bother. If you wish to use the
2395 function without official EVP_CIPHER structures, just declare
2396 a local one and set the key_len and iv_len fields to the
2399 The following routines perform encryption and decryption 'by parts'. By
2400 this I mean that there are groups of 3 routines. An Init function that is
2401 used to specify a cipher and initialise data structures. An Update routine
2402 that does encryption/decryption, one 'chunk' at a time. And finally a
2403 'Final' function that finishes the encryption/decryption process.
2404 All these functions take a EVP_CIPHER pointer to specify which cipher to
2405 encrypt/decrypt with. They also take a EVP_CIPHER_CTX object as an
2406 argument. This structure is used to hold the state information associated
2407 with the operation in progress.
2409 void EVP_EncryptInit(
2410 EVP_CIPHER_CTX *ctx,
2414 This function initialise a EVP_CIPHER_CTX for encryption using the
2415 cipher passed in the 'type' field. The cipher is initialised to use
2416 'key' as the key and 'iv' for the initialisation vector (if one is
2417 required). If the type, key or iv is NULL, the value currently in the
2418 EVP_CIPHER_CTX is reused. So to perform several decrypt
2419 using the same cipher, key and iv, initialise with the cipher,
2420 key and iv the first time and then for subsequent calls,
2421 reuse 'ctx' but pass NULL for type, key and iv. You must make sure
2422 to pass a key that is large enough for a particular cipher. I
2423 would suggest using the EVP_BytesToKey() function.
2425 void EVP_EncryptUpdate(
2426 EVP_CIPHER_CTX *ctx,
2431 This function takes 'inl' bytes from 'in' and outputs bytes
2432 encrypted by the cipher 'ctx' was initialised with into 'out'. The
2433 number of bytes written to 'out' is put into outl. If a particular
2434 cipher encrypts in blocks, less or more bytes than input may be
2435 output. Currently the largest block size used by supported ciphers
2436 is 8 bytes, so 'out' should have room for 'inl+7' bytes. Normally
2437 EVP_EncryptInit() is called once, followed by lots and lots of
2438 calls to EVP_EncryptUpdate, followed by a single EVP_EncryptFinal
2441 void EVP_EncryptFinal(
2442 EVP_CIPHER_CTX *ctx,
2445 Because quite a large number of ciphers are block ciphers, there is
2446 often an incomplete block to write out at the end of the
2447 encryption. EVP_EncryptFinal() performs processing on this last
2448 block. The last block in encoded in such a way that it is possible
2449 to determine how many bytes in the last block are valid. For 8 byte
2450 block size ciphers, if only 5 bytes in the last block are valid, the
2451 last three bytes will be filled with the value 3. If only 2 were
2452 valid, the other 6 would be filled with sixes. If all 8 bytes are
2453 valid, a extra 8 bytes are appended to the cipher stream containing
2454 nothing but 8 eights. These last bytes are output into 'out' and
2455 the number of bytes written is put into 'outl' These last bytes
2456 are output into 'out' and the number of bytes written is put into
2457 'outl'. This form of block cipher finalisation is compatible with
2458 PKCS-5. Please remember that even if you are using ciphers like
2459 RC4 that has no blocking and so the function will not write
2460 anything into 'out', it would still be a good idea to pass a
2461 variable for 'out' that can hold 8 bytes just in case the cipher is
2462 changed some time in the future. It should also be remembered
2463 that the EVP_CIPHER_CTX contains the password and so when one has
2464 finished encryption with a particular EVP_CIPHER_CTX, it is good
2465 practice to zero the structure
2466 (ie. memset(ctx,0,sizeof(EVP_CIPHER_CTX)).
2468 void EVP_DecryptInit(
2469 EVP_CIPHER_CTX *ctx,
2473 This function is basically the same as EVP_EncryptInit() accept that
2474 is prepares the EVP_CIPHER_CTX for decryption.
2476 void EVP_DecryptUpdate(
2477 EVP_CIPHER_CTX *ctx,
2482 This function is basically the same as EVP_EncryptUpdate()
2483 except that it performs decryption. There is one
2484 fundamental difference though. 'out' can not be the same as
2485 'in' for any ciphers with a block size greater than 1 if more
2486 than one call to EVP_DecryptUpdate() will be made. This
2487 is because this routine can hold a 'partial' block between
2488 calls. When a partial block is decrypted (due to more bytes
2489 being passed via this function, they will be written to 'out'
2490 overwriting the input bytes in 'in' that have not been read
2491 yet. From this it should also be noted that 'out' should
2492 be at least one 'block size' larger than 'inl'. This problem
2493 only occurs on the second and subsequent call to
2494 EVP_DecryptUpdate() when using a block cipher.
2496 int EVP_DecryptFinal(
2497 EVP_CIPHER_CTX *ctx,
2500 This function is different to EVP_EncryptFinal in that it 'removes'
2501 any padding bytes appended when the data was encrypted. Due to the
2502 way in which 1 to 8 bytes may have been appended when encryption
2503 using a block cipher, 'out' can end up with 0 to 7 bytes being put
2504 into it. When decoding the padding bytes, it is possible to detect
2505 an incorrect decryption. If the decryption appears to be wrong, 0
2506 is returned. If everything seems ok, 1 is returned. For ciphers
2507 with a block size of 1 (RC4), this function would normally not
2508 return any bytes and would always return 1. Just because this
2509 function returns 1 does not mean the decryption was correct. It
2510 would normally be wrong due to either the wrong key/iv or
2511 corruption of the cipher data fed to EVP_DecryptUpdate().
2512 As for EVP_EncryptFinal, it is a good idea to zero the
2513 EVP_CIPHER_CTX after use since the structure contains the key used
2514 to decrypt the data.
2516 The following Cipher routines are convenience routines that call either
2517 EVP_EncryptXxx or EVP_DecryptXxx depending on weather the EVP_CIPHER_CTX
2518 was setup to encrypt or decrypt.
2520 void EVP_CipherInit(
2521 EVP_CIPHER_CTX *ctx,
2526 This function take arguments that are the same as EVP_EncryptInit()
2527 and EVP_DecryptInit() except for the extra 'enc' flag. If 1, the
2528 EVP_CIPHER_CTX is setup for encryption, if 0, decryption.
2530 void EVP_CipherUpdate(
2531 EVP_CIPHER_CTX *ctx,
2536 Again this function calls either EVP_EncryptUpdate() or
2537 EVP_DecryptUpdate() depending on state in the 'ctx' structure.
2538 As noted for EVP_DecryptUpdate(), when this routine is used
2539 for decryption with block ciphers, 'out' should not be the
2542 int EVP_CipherFinal(
2543 EVP_CIPHER_CTX *ctx,
2544 unsigned char *outm,
2546 This routine call EVP_EncryptFinal() or EVP_DecryptFinal()
2547 depending on the state information in 'ctx'. 1 is always returned
2548 if the mode is encryption, otherwise the return value is the return
2549 value of EVP_DecryptFinal().
2551 ==== cipher.m ========================================================
2553 Date: Tue, 15 Oct 1996 08:16:14 +1000 (EST)
2554 From: Eric Young <eay@mincom.com>
2556 To: Roland Haring <rharing@tandem.cl>
2557 Cc: ssl-users@mincom.com
2558 Subject: Re: Symmetric encryption with ssleay
2559 In-Reply-To: <m0vBpyq-00001aC@tandemnet.tandem.cl>
2560 Message-Id: <Pine.SOL.3.91.961015075623.11394A-100000@orb>
2562 Content-Type: TEXT/PLAIN; charset=US-ASCII
2563 Sender: ssl-lists-owner@mincom.com
2568 On Fri, 11 Oct 1996, Roland Haring wrote:
2570 > Would somebody be so kind to give me the minimum basic
2571 > calls I need to do to libcrypto.a to get some text encrypted
2572 > and decrypted again? ...hopefully with code included to do
2573 > base64 encryption and decryption ... e.g. that sign-it.c code
2574 > posted some while ago was a big help :-) (please, do not point
2575 > me to apps/enc.c where I suspect my Heissenbug to be hidden :-)
2577 Ok, the base64 encoding stuff in 'enc.c' does the wrong thing sometimes
2578 when the data is less than a line long (this is for decoding). I'll dig
2579 up the exact fix today and post it. I am taking longer on 0.6.5 than I
2580 intended so I'll just post this patch.
2582 The documentation to read is in
2584 doc/encode.doc (very sparse :-).
2588 The basic calls to encrypt with say triple DES are
2591 char key[EVP_MAX_KEY_LENGTH];
2592 char iv[EVP_MAX_IV_LENGTH];
2594 unsigned char out[512+8];
2597 /* optional generation of key/iv data from text password using md5
2598 * via an upward compatable verson of PKCS#5. */
2599 EVP_BytesToKey(EVP_des_ede3_cbc,EVP_md5,NULL,passwd,strlen(passwd),
2602 /* Initalise the EVP_CIPHER_CTX */
2603 EVP_EncryptInit(ctx,EVP_des_ede3_cbc,key,iv);
2607 /* This is processing 512 bytes at a time, the bytes are being
2608 * copied into 'out', outl bytes are output. 'out' should not be the
2609 * same as 'in' for reasons mentioned in the documentation. */
2610 EVP_EncryptUpdate(ctx,out,&outl,in,512);
2613 /* Output the last 'block'. If the cipher is a block cipher, the last
2614 * block is encoded in such a way so that a wrong decryption will normally be
2615 * detected - again, one of the PKCS standards. */
2617 EVP_EncryptFinal(ctx,out,&outl);
2619 To decrypt, use the EVP_DecryptXXXXX functions except that EVP_DecryptFinal()
2620 will return 0 if the decryption fails (only detectable on block ciphers).
2626 which does either encryption or decryption depending on an extra
2627 parameter to EVP_CipherInit().
2630 To do the base64 encoding,
2639 where the encoding is quite simple, but the decoding can be a bit more
2640 fun (due to dud input).
2642 EVP_DecodeUpdate() returns -1 for an error on an input line, 0 if the
2643 'last line' was just processed, and 1 if more lines should be submitted.
2645 EVP_DecodeFinal() returns -1 for an error or 1 if things are ok.
2648 EVP_DecodeInit(....)
2651 i=EVP_DecodeUpdate(....);
2652 if (i < 0) goto err;
2654 /* process the data */
2658 EVP_DecodeFinal(....);
2659 /* process the data */
2661 The problem in 'enc.c' is that I was stuff the processing up after the
2662 EVP_DecodeFinal(...) when the for(..) loop was not being run (one line of
2663 base64 data) and this was because 'enc.c' tries to scan over a file until
2664 it hits the first valid base64 encoded line.
2666 hope this helps a bit.
2669 Eric Young | BOOL is tri-state according to Bill Gates.
2670 AARNet: eay@mincom.oz.au | RTFM Win32 GetMessage().
2672 ==== conf.doc ========================================================
2676 The CONF library is a simple set of routines that can be used to configure
2677 programs. It is a superset of the genenv() function with some extra
2680 The library consists of 5 functions.
2682 LHASH *CONF_load(LHASH *config,char *file);
2683 This function is called to load in a configuration file. Multiple
2684 configuration files can be loaded, with each subsequent 'load' overwriting
2685 any already defined 'variables'. If there is an error, NULL is returned.
2686 If config is NULL, a new LHASH structure is created and returned, otherwise
2687 the new data in the 'file' is loaded into the 'config' structure.
2689 void CONF_free(LHASH *config);
2690 This function free()s the data in config.
2692 char *CONF_get_string(LHASH *config,char *section,char *name);
2693 This function returns the string found in 'config' that corresponds to the
2694 'section' and 'name' specified. Classes and the naming system used will be
2695 discussed later in this document. If the variable is not defined, an NULL
2698 long CONF_get_long(LHASH *config,char *section, char *name);
2699 This function is the same as CONF_get_string() except that it converts the
2700 string to an long and returns it. If variable is not a number or the
2701 variable does not exist, 0 is returned. This is a little problematic but I
2702 don't know of a simple way around it.
2704 STACK *CONF_get_section(LHASH *config, char *section);
2705 This function returns a 'stack' of CONF_VALUE items that are all the
2706 items defined in a particular section. DO NOT free() any of the
2707 variable returned. They will disappear when CONF_free() is called.
2710 The configuration file is divided into 'sections'. Each section is started by
2711 a line of the form '[ section ]'. All subsequent variable definitions are
2712 of this section. A variable definition is a simple alpha-numeric name
2713 followed by an '=' and then the data. A section or variable name can be
2714 described by a regular expression of the following form '[A-Za-z0-9_]+'.
2715 The value of the variable is the text after the '=' until the end of the
2716 line, stripped of leading and trailing white space.
2717 At this point I should mention that a '#' is a comment character, \ is the
2718 escape character, and all three types of quote can be used to stop any
2719 special interpretation of the data.
2720 Now when the data is being loaded, variable expansion can occur. This is
2721 done by expanding any $NAME sequences into the value represented by the
2722 variable NAME. If the variable is not in the current section, the different
2723 section can be specified by using the $SECTION::NAME form. The ${NAME} form
2724 also works and is very useful for expanding variables inside strings.
2726 When a variable is looked up, there are 2 special section. 'default', which
2727 is the initial section, and 'ENV' which is the processes environment
2728 variables (accessed via getenv()). When a variable is looked up, it is
2729 first 'matched' with it's section (if one was specified), if this fails, the
2730 'default' section is matched.
2731 If the 'lhash' variable passed was NULL, the environment is searched.
2733 Now why do we bother with sections? So we can have multiple programs using
2734 the same configuration file, or multiple instances of the same program
2735 using different variables. It also provides a nice mechanism to override
2736 the processes environment variables (eg ENV::HOME=/tmp). If there is a
2737 program specific variable missing, we can have default values.
2738 Multiple configuration files can be loaded, with each new value clearing
2739 any predefined values. A system config file can provide 'default' values,
2740 and application/usr specific files can provide overriding values.
2744 # This is a simple example
2745 SSLEAY_HOME = /usr/local/ssl
2746 ENV::PATH = $SSLEAY_HOME/bin:$PATH # override my path
2749 cert_dir = $SSLEAY_HOME/certs # /usr/local/ssl/certs
2752 CIPHER = DES-EDE-MD5:RC4-MD5
2753 USER_CERT = $HOME/${USER}di'r 5' # /home/eay/eaydir 5
2754 USER_CERT = $HOME/\${USER}di\'r # /home/eay/${USER}di'r
2755 USER_CERT = "$HOME/${US"ER}di\'r # $HOME/${USER}di'r
2759 9ab # TEST=123456789ab
2760 TTT = 1234\n\n # TTT=1234<nl><nl>
2764 ==== des.doc ========================================================
2768 Please note that this library was originally written to operate with
2769 eBones, a version of Kerberos that had had encryption removed when it left
2770 the USA and then put back in. As such there are some routines that I will
2771 advise not using but they are still in the library for historical reasons.
2772 For all calls that have an 'input' and 'output' variables, they can be the
2775 This library requires the inclusion of 'des.h'.
2777 All of the encryption functions take what is called a des_key_schedule as an
2778 argument. A des_key_schedule is an expanded form of the des key.
2779 A des_key is 8 bytes of odd parity, the type used to hold the key is a
2780 des_cblock. A des_cblock is an array of 8 bytes, often in this library
2781 description I will refer to input bytes when the function specifies
2782 des_cblock's as input or output, this just means that the variable should
2783 be a multiple of 8 bytes.
2785 The define DES_ENCRYPT is passed to specify encryption, DES_DECRYPT to
2786 specify decryption. The functions and global variable are as follows:
2789 DES keys are supposed to be odd parity. If this variable is set to
2790 a non-zero value, des_set_key() will check that the key has odd
2791 parity and is not one of the known weak DES keys. By default this
2792 variable is turned off;
2794 void des_set_odd_parity(
2796 This function takes a DES key (8 bytes) and sets the parity to odd.
2798 int des_is_weak_key(
2800 This function returns a non-zero value if the DES key passed is a
2801 weak, DES key. If it is a weak key, don't use it, try a different
2802 one. If you are using 'random' keys, the chances of hitting a weak
2803 key are 1/2^52 so it is probably not worth checking for them.
2807 des_key_schedule schedule);
2808 Des_set_key converts an 8 byte DES key into a des_key_schedule.
2809 A des_key_schedule is an expanded form of the key which is used to
2810 perform actual encryption. It can be regenerated from the DES key
2811 so it only needs to be kept when encryption or decryption is about
2812 to occur. Don't save or pass around des_key_schedule's since they
2813 are CPU architecture dependent, DES keys are not. If des_check_key
2814 is non zero, zero is returned if the key has the wrong parity or
2815 the key is a weak key, else 1 is returned.
2819 des_key_schedule schedule);
2820 An alternative name for des_set_key().
2822 int des_rw_mode; /* defaults to DES_PCBC_MODE */
2823 This flag holds either DES_CBC_MODE or DES_PCBC_MODE (default).
2824 This specifies the function to use in the enc_read() and enc_write()
2828 unsigned long *data,
2829 des_key_schedule ks,
2831 This is the DES encryption function that gets called by just about
2832 every other DES routine in the library. You should not use this
2833 function except to implement 'modes' of DES. I say this because the
2834 functions that call this routine do the conversion from 'char *' to
2835 long, and this needs to be done to make sure 'non-aligned' memory
2836 access do not occur. The characters are loaded 'little endian',
2837 have a look at my source code for more details on how I use this
2839 Data is a pointer to 2 unsigned long's and ks is the
2840 des_key_schedule to use. enc, is non zero specifies encryption,
2844 unsigned long *data,
2845 des_key_schedule ks,
2847 This functions is the same as des_encrypt() except that the DES
2848 initial permutation (IP) and final permutation (FP) have been left
2849 out. As for des_encrypt(), you should not use this function.
2850 It is used by the routines in my library that implement triple DES.
2851 IP() des_encrypt2() des_encrypt2() des_encrypt2() FP() is the same
2852 as des_encrypt() des_encrypt() des_encrypt() except faster :-).
2854 void des_ecb_encrypt(
2857 des_key_schedule ks,
2859 This is the basic Electronic Code Book form of DES, the most basic
2860 form. Input is encrypted into output using the key represented by
2861 ks. If enc is non zero (DES_ENCRYPT), encryption occurs, otherwise
2862 decryption occurs. Input is 8 bytes long and output is 8 bytes.
2863 (the des_cblock structure is 8 chars).
2865 void des_ecb3_encrypt(
2868 des_key_schedule ks1,
2869 des_key_schedule ks2,
2870 des_key_schedule ks3,
2872 This is the 3 key EDE mode of ECB DES. What this means is that
2873 the 8 bytes of input is encrypted with ks1, decrypted with ks2 and
2874 then encrypted again with ks3, before being put into output;
2875 C=E(ks3,D(ks2,E(ks1,M))). There is a macro, des_ecb2_encrypt()
2876 that only takes 2 des_key_schedules that implements,
2877 C=E(ks1,D(ks2,E(ks1,M))) in that the final encrypt is done with ks1.
2879 void des_cbc_encrypt(
2883 des_key_schedule ks,
2886 This routine implements DES in Cipher Block Chaining mode.
2887 Input, which should be a multiple of 8 bytes is encrypted
2888 (or decrypted) to output which will also be a multiple of 8 bytes.
2889 The number of bytes is in length (and from what I've said above,
2890 should be a multiple of 8). If length is not a multiple of 8, I'm
2891 not being held responsible :-). ivec is the initialisation vector.
2892 This function does not modify this variable. To correctly implement
2893 cbc mode, you need to do one of 2 things; copy the last 8 bytes of
2894 cipher text for use as the next ivec in your application,
2895 or use des_ncbc_encrypt().
2896 Only this routine has this problem with updating the ivec, all
2897 other routines that are implementing cbc mode update ivec.
2899 void des_ncbc_encrypt(
2903 des_key_schedule sk,
2906 For historical reasons, des_cbc_encrypt() did not update the
2907 ivec with the value requires so that subsequent calls to
2908 des_cbc_encrypt() would 'chain'. This was needed so that the same
2909 'length' values would not need to be used when decrypting.
2910 des_ncbc_encrypt() does the right thing. It is the same as
2911 des_cbc_encrypt accept that ivec is updates with the correct value
2912 to pass in subsequent calls to des_ncbc_encrypt(). I advise using
2913 des_ncbc_encrypt() instead of des_cbc_encrypt();
2915 void des_xcbc_encrypt(
2919 des_key_schedule sk,
2924 This is RSA's DESX mode of DES. It uses inw and outw to
2925 'whiten' the encryption. inw and outw are secret (unlike the iv)
2926 and are as such, part of the key. So the key is sort of 24 bytes.
2927 This is much better than cbc des.
2929 void des_3cbc_encrypt(
2933 des_key_schedule sk1,
2934 des_key_schedule sk2,
2938 This function is flawed, do not use it. I have left it in the
2939 library because it is used in my des(1) program and will function
2940 correctly when used by des(1). If I removed the function, people
2941 could end up unable to decrypt files.
2942 This routine implements outer triple cbc encryption using 2 ks and
2943 2 ivec's. Use des_ede2_cbc_encrypt() instead.
2945 void des_ede3_cbc_encrypt(
2949 des_key_schedule ks1,
2950 des_key_schedule ks2,
2951 des_key_schedule ks3,
2954 This function implements outer triple CBC DES encryption with 3
2955 keys. What this means is that each 'DES' operation
2956 inside the cbc mode is really an C=E(ks3,D(ks2,E(ks1,M))).
2957 Again, this is cbc mode so an ivec is requires.
2958 This mode is used by SSL.
2959 There is also a des_ede2_cbc_encrypt() that only uses 2
2960 des_key_schedule's, the first being reused for the final
2961 encryption. C=E(ks1,D(ks2,E(ks1,M))). This form of triple DES
2962 is used by the RSAref library.
2964 void des_pcbc_encrypt(
2968 des_key_schedule ks,
2971 This is Propagating Cipher Block Chaining mode of DES. It is used
2972 by Kerberos v4. It's parameters are the same as des_ncbc_encrypt().
2974 void des_cfb_encrypt(
2979 des_key_schedule ks,
2982 Cipher Feedback Back mode of DES. This implementation 'feeds back'
2983 in numbit blocks. The input (and output) is in multiples of numbits
2984 bits. numbits should to be a multiple of 8 bits. Length is the
2985 number of bytes input. If numbits is not a multiple of 8 bits,
2986 the extra bits in the bytes will be considered padding. So if
2987 numbits is 12, for each 2 input bytes, the 4 high bits of the
2988 second byte will be ignored. So to encode 72 bits when using
2989 a numbits of 12 take 12 bytes. To encode 72 bits when using
2990 numbits of 9 will take 16 bytes. To encode 80 bits when using
2991 numbits of 16 will take 10 bytes. etc, etc. This padding will
2992 apply to both input and output.
2995 void des_cfb64_encrypt(
2999 des_key_schedule ks,
3003 This is one of the more useful functions in this DES library, it
3004 implements CFB mode of DES with 64bit feedback. Why is this
3005 useful you ask? Because this routine will allow you to encrypt an
3006 arbitrary number of bytes, no 8 byte padding. Each call to this
3007 routine will encrypt the input bytes to output and then update ivec
3008 and num. num contains 'how far' we are though ivec. If this does
3009 not make much sense, read more about cfb mode of DES :-).
3011 void des_ede3_cfb64_encrypt(
3015 des_key_schedule ks1,
3016 des_key_schedule ks2,
3017 des_key_schedule ks3,
3021 Same as des_cfb64_encrypt() accept that the DES operation is
3022 triple DES. As usual, there is a macro for
3023 des_ede2_cfb64_encrypt() which reuses ks1.
3025 void des_ofb_encrypt(
3030 des_key_schedule ks,
3032 This is a implementation of Output Feed Back mode of DES. It is
3033 the same as des_cfb_encrypt() in that numbits is the size of the
3034 units dealt with during input and output (in bits).
3036 void des_ofb64_encrypt(
3040 des_key_schedule ks,
3043 The same as des_cfb64_encrypt() except that it is Output Feed Back
3046 void des_ede3_ofb64_encrypt(
3050 des_key_schedule ks1,
3051 des_key_schedule ks2,
3052 des_key_schedule ks3,
3055 Same as des_ofb64_encrypt() accept that the DES operation is
3056 triple DES. As usual, there is a macro for
3057 des_ede2_ofb64_encrypt() which reuses ks1.
3059 int des_read_pw_string(
3064 This routine is used to get a password from the terminal with echo
3065 turned off. Buf is where the string will end up and length is the
3066 size of buf. Prompt is a string presented to the 'user' and if
3067 verify is set, the key is asked for twice and unless the 2 copies
3068 match, an error is returned. A return code of -1 indicates a
3069 system error, 1 failure due to use interaction, and 0 is success.
3071 unsigned long des_cbc_cksum(
3075 des_key_schedule ks,
3077 This function produces an 8 byte checksum from input that it puts in
3078 output and returns the last 4 bytes as a long. The checksum is
3079 generated via cbc mode of DES in which only the last 8 byes are
3080 kept. I would recommend not using this function but instead using
3081 the EVP_Digest routines, or at least using MD5 or SHA. This
3082 function is used by Kerberos v4 so that is why it stays in the
3089 This is my fast version of the unix crypt(3) function. This version
3090 takes only a small amount of space relative to other fast
3091 crypt() implementations. This is different to the normal crypt
3092 in that the third parameter is the buffer that the return value
3093 is written into. It needs to be at least 14 bytes long. This
3094 function is thread safe, unlike the normal crypt.
3099 This function calls des_fcrypt() with a static array passed as the
3100 third parameter. This emulates the normal non-thread safe semantics
3103 void des_string_to_key(
3106 This function takes str and converts it into a DES key. I would
3107 recommend using MD5 instead and use the first 8 bytes of output.
3108 When I wrote the first version of these routines back in 1990, MD5
3109 did not exist but I feel these routines are still sound. This
3110 routines is compatible with the one in MIT's libdes.
3112 void des_string_to_2keys(
3116 This function takes str and converts it into 2 DES keys.
3117 I would recommend using MD5 and using the 16 bytes as the 2 keys.
3118 I have nothing against these 2 'string_to_key' routines, it's just
3119 that if you say that your encryption key is generated by using the
3120 16 bytes of an MD5 hash, every-one knows how you generated your
3123 int des_read_password(
3127 This routine combines des_read_pw_string() with des_string_to_key().
3129 int des_read_2passwords(
3134 This routine combines des_read_pw_string() with des_string_to_2key().
3136 void des_random_seed(
3138 This routine sets a starting point for des_random_key().
3140 void des_random_key(
3142 This function return a random key. Make sure to 'seed' the random
3143 number generator (with des_random_seed()) before using this function.
3144 I personally now use a MD5 based random number system.
3150 des_key_schedule ks,
3152 This function will write to a file descriptor the encrypted data
3153 from buf. This data will be preceded by a 4 byte 'byte count' and
3154 will be padded out to 8 bytes. The encryption is either CBC of
3155 PCBC depending on the value of des_rw_mode. If it is DES_PCBC_MODE,
3156 pcbc is used, if DES_CBC_MODE, cbc is used. The default is to use
3163 des_key_schedule ks,
3165 This routines read stuff written by des_enc_read() and decrypts it.
3166 I have used these routines quite a lot but I don't believe they are
3167 suitable for non-blocking io. If you are after a full
3168 authentication/encryption over networks, have a look at SSL instead.
3170 unsigned long des_quad_cksum(
3176 This is a function from Kerberos v4 that is not anything to do with
3177 DES but was needed. It is a cksum that is quicker to generate than
3178 des_cbc_cksum(); I personally would use MD5 routines now.
3181 Quite a bit of the following information has been taken from
3184 Electronic funds transfer - Requirements for interfaces,
3185 Part 5.2: Modes of operation for an n-bit block cipher algorithm
3188 There are several different modes in which DES can be used, they are
3191 Electronic Codebook Mode (ECB) (des_ecb_encrypt())
3192 - 64 bits are enciphered at a time.
3193 - The order of the blocks can be rearranged without detection.
3194 - The same plaintext block always produces the same ciphertext block
3195 (for the same key) making it vulnerable to a 'dictionary attack'.
3196 - An error will only affect one ciphertext block.
3198 Cipher Block Chaining Mode (CBC) (des_cbc_encrypt())
3199 - a multiple of 64 bits are enciphered at a time.
3200 - The CBC mode produces the same ciphertext whenever the same
3201 plaintext is encrypted using the same key and starting variable.
3202 - The chaining operation makes the ciphertext blocks dependent on the
3203 current and all preceding plaintext blocks and therefore blocks can not
3205 - The use of different starting variables prevents the same plaintext
3206 enciphering to the same ciphertext.
3207 - An error will affect the current and the following ciphertext blocks.
3209 Cipher Feedback Mode (CFB) (des_cfb_encrypt())
3210 - a number of bits (j) <= 64 are enciphered at a time.
3211 - The CFB mode produces the same ciphertext whenever the same
3212 plaintext is encrypted using the same key and starting variable.
3213 - The chaining operation makes the ciphertext variables dependent on the
3214 current and all preceding variables and therefore j-bit variables are
3215 chained together and can not be rearranged.
3216 - The use of different starting variables prevents the same plaintext
3217 enciphering to the same ciphertext.
3218 - The strength of the CFB mode depends on the size of k (maximal if
3219 j == k). In my implementation this is always the case.
3220 - Selection of a small value for j will require more cycles through
3221 the encipherment algorithm per unit of plaintext and thus cause
3222 greater processing overheads.
3223 - Only multiples of j bits can be enciphered.
3224 - An error will affect the current and the following ciphertext variables.
3226 Output Feedback Mode (OFB) (des_ofb_encrypt())
3227 - a number of bits (j) <= 64 are enciphered at a time.
3228 - The OFB mode produces the same ciphertext whenever the same
3229 plaintext enciphered using the same key and starting variable. More
3230 over, in the OFB mode the same key stream is produced when the same
3231 key and start variable are used. Consequently, for security reasons
3232 a specific start variable should be used only once for a given key.
3233 - The absence of chaining makes the OFB more vulnerable to specific attacks.
3234 - The use of different start variables values prevents the same
3235 plaintext enciphering to the same ciphertext, by producing different
3237 - Selection of a small value for j will require more cycles through
3238 the encipherment algorithm per unit of plaintext and thus cause
3239 greater processing overheads.
3240 - Only multiples of j bits can be enciphered.
3241 - OFB mode of operation does not extend ciphertext errors in the
3242 resultant plaintext output. Every bit error in the ciphertext causes
3243 only one bit to be in error in the deciphered plaintext.
3244 - OFB mode is not self-synchronising. If the two operation of
3245 encipherment and decipherment get out of synchronism, the system needs
3246 to be re-initialised.
3247 - Each re-initialisation should use a value of the start variable
3248 different from the start variable values used before with the same
3249 key. The reason for this is that an identical bit stream would be
3250 produced each time from the same parameters. This would be
3251 susceptible to a ' known plaintext' attack.
3253 Triple ECB Mode (des_ecb3_encrypt())
3254 - Encrypt with key1, decrypt with key2 and encrypt with key3 again.
3255 - As for ECB encryption but increases the key length to 168 bits.
3256 There are theoretic attacks that can be used that make the effective
3257 key length 112 bits, but this attack also requires 2^56 blocks of
3258 memory, not very likely, even for the NSA.
3259 - If both keys are the same it is equivalent to encrypting once with
3261 - If the first and last key are the same, the key length is 112 bits.
3262 There are attacks that could reduce the key space to 55 bit's but it
3263 requires 2^56 blocks of memory.
3264 - If all 3 keys are the same, this is effectively the same as normal
3267 Triple CBC Mode (des_ede3_cbc_encrypt())
3268 - Encrypt with key1, decrypt with key2 and then encrypt with key3.
3269 - As for CBC encryption but increases the key length to 168 bits with
3270 the same restrictions as for triple ecb mode.
3272 ==== digest.doc ========================================================
3275 The Message Digest subroutines.
3277 These routines require "evp.h" to be included.
3279 These functions are a higher level interface to the various message digest
3280 routines found in this library. As such, they allow the same code to be
3281 used to digest via different algorithms with only a change in an initial
3282 parameter. They are basically just a front-end to the MD2, MD5, SHA
3286 These routines all take a pointer to the following structure to specify
3287 which message digest algorithm to use.
3288 typedef struct evp_md_st
3297 int required_pkey_type; /*EVP_PKEY_xxx */
3302 If additional message digest algorithms are to be supported, a structure of
3303 this type needs to be declared and populated and then the Digest routines
3304 can be used with that algorithm. The type field is the object NID of the
3305 digest type (read the section on Objects for an explanation). The pkey_type
3306 is the Object type to use when the a message digest is generated by there
3307 routines and then is to be signed with the pkey algorithm. Md_size is
3308 the size of the message digest returned. Init, update
3309 and final are the relevant functions to perform the message digest function
3310 by parts. One reason for specifying the message digest to use via this
3311 mechanism is that if you only use md5, only the md5 routines will
3312 be included in you linked program. If you passed an integer
3313 that specified which message digest to use, the routine that mapped that
3314 integer to a set of message digest functions would cause all the message
3315 digests functions to be link into the code. This setup also allows new
3316 message digest functions to be added by the application.
3318 The six message digests defined in this library are
3320 EVP_MD *EVP_md2(void); /* RSA sign/verify */
3321 EVP_MD *EVP_md5(void); /* RSA sign/verify */
3322 EVP_MD *EVP_sha(void); /* RSA sign/verify */
3323 EVP_MD *EVP_sha1(void); /* RSA sign/verify */
3324 EVP_MD *EVP_dss(void); /* DSA sign/verify */
3325 EVP_MD *EVP_dss1(void); /* DSA sign/verify */
3327 All the message digest routines take a EVP_MD_CTX pointer as an argument.
3328 The state of the message digest is kept in this structure.
3330 typedef struct pem_md_ctx_st
3334 unsigned char base[4]; /* this is used in my library as a
3335 * 'pointer' to all union elements
3343 The Digest functions are as follows.
3345 void EVP_DigestInit(
3348 This function is used to initialise the EVP_MD_CTX. The message
3349 digest that will associated with 'ctx' is specified by 'type'.
3351 void EVP_DigestUpdate(
3353 unsigned char *data,
3355 This function is used to pass more data to the message digest
3356 function. 'cnt' bytes are digested from 'data'.
3358 void EVP_DigestFinal(
3362 This function finishes the digestion and puts the message digest
3363 into 'md'. The length of the message digest is put into len;
3364 EVP_MAX_MD_SIZE is the size of the largest message digest that
3365 can be returned from this function. Len can be NULL if the
3366 size of the digest is not required.
3369 ==== encode.doc ========================================================
3372 void EVP_EncodeInit(EVP_ENCODE_CTX *ctx);
3373 void EVP_EncodeUpdate(EVP_ENCODE_CTX *ctx,unsigned char *out,
3374 int *outl,unsigned char *in,int inl);
3375 void EVP_EncodeFinal(EVP_ENCODE_CTX *ctx,unsigned char *out,int *outl);
3376 int EVP_EncodeBlock(unsigned char *t, unsigned char *f, int n);
3378 void EVP_DecodeInit(EVP_ENCODE_CTX *ctx);
3379 int EVP_DecodeUpdate(EVP_ENCODE_CTX *ctx,unsigned char *out,int *outl,
3380 unsigned char *in, int inl);
3381 int EVP_DecodeFinal(EVP_ENCODE_CTX *ctx, unsigned
3382 char *out, int *outl);
3383 int EVP_DecodeBlock(unsigned char *t, unsigned
3387 ==== envelope.doc ========================================================
3389 The following routines are use to create 'digital' envelopes.
3390 By this I mean that they perform various 'higher' level cryptographic
3391 functions. Have a read of 'cipher.doc' and 'digest.doc' since those
3392 routines are used by these functions.
3393 cipher.doc contains documentation about the cipher part of the
3394 envelope library and digest.doc contatins the description of the
3395 message digests supported.
3397 To 'sign' a document involves generating a message digest and then encrypting
3398 the digest with an private key.
3400 #define EVP_SignInit(a,b) EVP_DigestInit(a,b)
3401 #define EVP_SignUpdate(a,b,c) EVP_DigestUpdate(a,b,c)
3402 Due to the fact this operation is basically just an extended message
3403 digest, the first 2 functions are macro calls to Digest generating
3411 This finalisation function finishes the generation of the message
3412 digest and then encrypts the digest (with the correct message digest
3413 object identifier) with the EVP_PKEY private key. 'ctx' is the message digest
3414 context. 'md' will end up containing the encrypted message digest. This
3415 array needs to be EVP_PKEY_size(pkey) bytes long. 's' will actually
3416 contain the exact length. 'pkey' of course is the private key. It is
3417 one of EVP_PKEY_RSA or EVP_PKEY_DSA type.
3418 If there is an error, 0 is returned, otherwise 1.
3420 Verify is used to check an signed message digest.
3422 #define EVP_VerifyInit(a,b) EVP_DigestInit(a,b)
3423 #define EVP_VerifyUpdate(a,b,c) EVP_DigestUpdate(a,b,c)
3424 Since the first step is to generate a message digest, the first 2 functions
3427 int EVP_VerifyFinal(
3432 This function finishes the generation of the message digest and then
3433 compares it with the supplied encrypted message digest. 'md' contains the
3434 's' bytes of encrypted message digest. 'pkey' is used to public key decrypt
3435 the digest. It is then compared with the message digest just generated.
3436 If they match, 1 is returned else 0.
3438 int EVP_SealInit(EVP_CIPHER_CTX *ctx, EVP_CIPHER *type, unsigned char **ek,
3439 int *ekl, unsigned char *iv, EVP_PKEY **pubk, int npubk);
3440 Must have at least one public key, error is 0. I should also mention that
3441 the buffers pointed to by 'ek' need to be EVP_PKEY_size(pubk[n]) is size.
3443 #define EVP_SealUpdate(a,b,c,d,e) EVP_EncryptUpdate(a,b,c,d,e)
3444 void EVP_SealFinal(EVP_CIPHER_CTX *ctx,unsigned char *out,int *outl);
3447 int EVP_OpenInit(EVP_CIPHER_CTX *ctx,EVP_CIPHER *type,unsigned char *ek,
3448 int ekl,unsigned char *iv,EVP_PKEY *priv);
3451 #define EVP_OpenUpdate(a,b,c,d,e) EVP_DecryptUpdate(a,b,c,d,e)
3453 int EVP_OpenFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl);
3454 Decrypt final return code
3457 ==== error.doc ========================================================
3461 The 'error' system I've implemented is intended to server 2 purpose, to
3462 record the reason why a command failed and to record where in the libraries
3463 the failure occurred. It is more or less setup to record a 'trace' of which
3464 library components were being traversed when the error occurred.
3466 When an error is recorded, it is done so a as single unsigned long which is
3467 composed of three parts. The top byte is the 'library' number, the middle
3468 12 bytes is the function code, and the bottom 12 bits is the 'reason' code.
3470 Each 'library', or should a say, 'section' of the SSLeay library has a
3471 different unique 'library' error number. Each function in the library has
3472 a number that is unique for that library. Each 'library' also has a number
3473 for each 'error reason' that is only unique for that 'library'.
3475 Due to the way these error routines record a 'error trace', there is an
3476 array per thread that is used to store the error codes.
3477 The various functions in this library are used to access
3478 and manipulate this array.
3480 void ERR_put_error(int lib, int func,int reason);
3481 This routine records an error in library 'lib', function 'func'
3482 and reason 'reason'. As errors get 'put' into the buffer, they wrap
3483 around and overwrite old errors if too many are written. It is assumed
3484 that the last errors are the most important.
3486 unsigned long ERR_get_error(void );
3487 This function returns the last error added to the error buffer.
3488 In effect it is popping the value off the buffer so repeated calls will
3489 continue to return values until there are no more errors to return in which
3492 unsigned long ERR_peek_error(void );
3493 This function returns the value of the last error added to the
3494 error buffer but does not 'pop' it from the buffer.
3496 void ERR_clear_error(void );
3497 This function clears the error buffer, discarding all unread
3500 While the above described error system obviously produces lots of different
3501 error number, a method for 'reporting' these errors in a human readable
3502 form is required. To achieve this, each library has the option of
3503 'registering' error strings.
3505 typedef struct ERR_string_data_st
3507 unsigned long error;
3511 The 'ERR_STRING_DATA' contains an error code and the corresponding text
3512 string. To add new function error strings for a library, the
3513 ERR_STRING_DATA needs to be 'registered' with the library.
3515 void ERR_load_strings(unsigned long lib,ERR_STRING_DATA *err);
3516 This function 'registers' the array of ERR_STRING_DATA pointed to by
3517 'err' as error text strings for the error library 'lib'.
3519 void ERR_free_strings(void);
3520 This function free()s all the loaded error strings.
3522 char *ERR_error_string(unsigned long error,char *buf);
3523 This function returns a text string that is a human readable
3524 version of the error represented by 'error'. Buff should be at least 120
3525 bytes long and if it is NULL, the return value is a pointer to a static
3526 variable that will contain the error string, otherwise 'buf' is returned.
3527 If there is not a text string registered for a particular error, a text
3528 string containing the error number is returned instead.
3530 void ERR_print_errors(BIO *bp);
3531 void ERR_print_errors_fp(FILE *fp);
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