5 Any keypair function here that gets deprecated should be moved to
12 d2i_ACCESS_DESCRIPTION,
16 d2i_ASIdentifierChoice,
21 d2i_ASN1_GENERALIZEDTIME,
22 d2i_ASN1_GENERALSTRING,
27 d2i_ASN1_OCTET_STRING,
29 d2i_ASN1_PRINTABLESTRING,
30 d2i_ASN1_SEQUENCE_ANY,
36 d2i_ASN1_UNIVERSALSTRING,
39 d2i_ASN1_VISIBLESTRING,
41 d2i_AUTHORITY_INFO_ACCESS,
43 d2i_BASIC_CONSTRAINTS,
44 d2i_CERTIFICATEPOLICIES,
46 d2i_CMS_ReceiptRequest,
55 d2i_DSAPrivateKey_bio,
75 d2i_ESS_ISSUER_SERIAL,
77 d2i_ESS_SIGNING_CERT_V2,
78 d2i_EXTENDED_KEY_USAGE,
86 d2i_ISSUING_DIST_POINT,
88 d2i_NETSCAPE_CERT_SEQUENCE,
103 d2i_OCSP_REVOKEDINFO,
108 d2i_OSSL_CMP_PKIHEADER,
110 d2i_OSSL_CRMF_CERTID,
111 d2i_OSSL_CRMF_CERTTEMPLATE,
112 d2i_OSSL_CRMF_ENCRYPTEDVALUE,
115 d2i_OSSL_CRMF_PBMPARAMETER,
116 d2i_OSSL_CRMF_PKIPUBLICATIONINFO,
117 d2i_OSSL_CRMF_SINGLEPUBINFO,
131 d2i_PKCS7_ENC_CONTENT,
133 d2i_PKCS7_ISSUER_AND_SERIAL,
134 d2i_PKCS7_RECIP_INFO,
136 d2i_PKCS7_SIGNER_INFO,
137 d2i_PKCS7_SIGN_ENVELOPE,
140 d2i_PKCS8_PRIV_KEY_INFO,
141 d2i_PKCS8_PRIV_KEY_INFO_bio,
142 d2i_PKCS8_PRIV_KEY_INFO_fp,
145 d2i_PKEY_USAGE_PERIOD,
149 d2i_PROXY_CERT_INFO_EXTENSION,
159 d2i_TS_MSG_IMPRINT_bio,
160 d2i_TS_MSG_IMPRINT_fp,
196 i2d_ACCESS_DESCRIPTION,
198 i2d_ADMISSION_SYNTAX,
200 i2d_ASIdentifierChoice,
205 i2d_ASN1_GENERALIZEDTIME,
206 i2d_ASN1_GENERALSTRING,
211 i2d_ASN1_OCTET_STRING,
213 i2d_ASN1_PRINTABLESTRING,
214 i2d_ASN1_SEQUENCE_ANY,
219 i2d_ASN1_UNIVERSALSTRING,
222 i2d_ASN1_VISIBLESTRING,
225 i2d_AUTHORITY_INFO_ACCESS,
227 i2d_BASIC_CONSTRAINTS,
228 i2d_CERTIFICATEPOLICIES,
230 i2d_CMS_ReceiptRequest,
239 i2d_DSAPrivateKey_bio,
240 i2d_DSAPrivateKey_fp,
251 i2d_ECPrivateKey_bio,
259 i2d_ESS_ISSUER_SERIAL,
260 i2d_ESS_SIGNING_CERT,
261 i2d_ESS_SIGNING_CERT_V2,
262 i2d_EXTENDED_KEY_USAGE,
267 i2d_IPAddressOrRange,
269 i2d_ISSUER_SIGN_TOOL,
270 i2d_ISSUING_DIST_POINT,
271 i2d_NAMING_AUTHORITY,
272 i2d_NETSCAPE_CERT_SEQUENCE,
287 i2d_OCSP_REVOKEDINFO,
292 i2d_OSSL_CMP_PKIHEADER,
294 i2d_OSSL_CRMF_CERTID,
295 i2d_OSSL_CRMF_CERTTEMPLATE,
296 i2d_OSSL_CRMF_ENCRYPTEDVALUE,
299 i2d_OSSL_CRMF_PBMPARAMETER,
300 i2d_OSSL_CRMF_PKIPUBLICATIONINFO,
301 i2d_OSSL_CRMF_SINGLEPUBINFO,
315 i2d_PKCS7_ENC_CONTENT,
317 i2d_PKCS7_ISSUER_AND_SERIAL,
319 i2d_PKCS7_RECIP_INFO,
321 i2d_PKCS7_SIGNER_INFO,
322 i2d_PKCS7_SIGN_ENVELOPE,
325 i2d_PKCS8PrivateKeyInfo_bio,
326 i2d_PKCS8PrivateKeyInfo_fp,
327 i2d_PKCS8_PRIV_KEY_INFO,
328 i2d_PKCS8_PRIV_KEY_INFO_bio,
329 i2d_PKCS8_PRIV_KEY_INFO_fp,
332 i2d_PKEY_USAGE_PERIOD,
336 i2d_PROXY_CERT_INFO_EXTENSION,
346 i2d_TS_MSG_IMPRINT_bio,
347 i2d_TS_MSG_IMPRINT_fp,
383 - convert objects from/to ASN.1/DER representation
389 TYPE *d2i_TYPE(TYPE **a, const unsigned char **ppin, long length);
390 TYPE *d2i_TYPE_bio(BIO *bp, TYPE **a);
391 TYPE *d2i_TYPE_fp(FILE *fp, TYPE **a);
393 int i2d_TYPE(const TYPE *a, unsigned char **ppout);
394 int i2d_TYPE(TYPE *a, unsigned char **ppout);
395 int i2d_TYPE_fp(FILE *fp, const TYPE *a);
396 int i2d_TYPE_fp(FILE *fp, TYPE *a);
397 int i2d_TYPE_bio(BIO *bp, const TYPE *a);
398 int i2d_TYPE_bio(BIO *bp, TYPE *a);
402 In the description here, B<I<TYPE>> is used a placeholder
403 for any of the OpenSSL datatypes, such as B<X509_CRL>.
404 The function parameters I<ppin> and I<ppout> are generally
405 either both named I<pp> in the headers, or I<in> and I<out>.
407 These functions convert OpenSSL objects to and from their ASN.1/DER
408 encoding. Unlike the C structures which can have pointers to sub-objects
409 within, the DER is a serialized encoding, suitable for sending over the
410 network, writing to a file, and so on.
412 B<d2i_I<TYPE>>() attempts to decode I<len> bytes at I<*ppin>. If successful a
413 pointer to the B<I<TYPE>> structure is returned and I<*ppin> is incremented to
414 the byte following the parsed data. If I<a> is not NULL then a pointer
415 to the returned structure is also written to I<*a>. If an error occurred
416 then NULL is returned.
418 On a successful return, if I<*a> is not NULL then it is assumed that I<*a>
419 contains a valid B<I<TYPE>> structure and an attempt is made to reuse it. This
420 "reuse" capability is present for historical compatibility but its use is
421 B<strongly discouraged> (see BUGS below, and the discussion in the RETURN
424 B<d2i_I<TYPE>_bio>() is similar to B<d2i_I<TYPE>>() except it attempts
425 to parse data from BIO I<bp>.
427 B<d2i_I<TYPE>_fp>() is similar to B<d2i_I<TYPE>>() except it attempts
428 to parse data from FILE pointer I<fp>.
430 B<i2d_I<TYPE>>() encodes the structure pointed to by I<a> into DER format.
431 If I<ppout> is not NULL, it writes the DER encoded data to the buffer
432 at I<*ppout>, and increments it to point after the data just written.
433 If the return value is negative an error occurred, otherwise it
434 returns the length of the encoded data.
436 If I<*ppout> is NULL memory will be allocated for a buffer and the encoded
437 data written to it. In this case I<*ppout> is not incremented and it points
438 to the start of the data just written.
440 B<i2d_I<TYPE>_bio>() is similar to B<i2d_I<TYPE>>() except it writes
441 the encoding of the structure I<a> to BIO I<bp> and it
442 returns 1 for success and 0 for failure.
444 B<i2d_I<TYPE>_fp>() is similar to B<i2d_I<TYPE>>() except it writes
445 the encoding of the structure I<a> to FILE pointer I<fp> and it
446 returns 1 for success and 0 for failure.
448 These routines do not encrypt private keys and therefore offer no
449 security; use L<PEM_write_PrivateKey(3)> or similar for writing to files.
453 The letters B<i> and B<d> in B<i2d_I<TYPE>>() stand for
454 "internal" (that is, an internal C structure) and "DER" respectively.
455 So B<i2d_I<TYPE>>() converts from internal to DER.
457 The functions can also understand B<BER> forms.
459 The actual TYPE structure passed to B<i2d_I<TYPE>>() must be a valid
460 populated B<I<TYPE>> structure -- it B<cannot> simply be fed with an
461 empty structure such as that returned by TYPE_new().
463 The encoded data is in binary form and may contain embedded zeros.
464 Therefore, any FILE pointers or BIOs should be opened in binary mode.
465 Functions such as strlen() will B<not> return the correct length
466 of the encoded structure.
468 The ways that I<*ppin> and I<*ppout> are incremented after the operation
469 can trap the unwary. See the B<WARNINGS> section for some common
471 The reason for this-auto increment behaviour is to reflect a typical
472 usage of ASN1 functions: after one structure is encoded or decoded
473 another will be processed after it.
475 The following points about the data types might be useful:
481 Represents an ASN1 OBJECT IDENTIFIER.
485 Represents a PKCS#3 DH parameters structure.
489 Represents an ANSI X9.42 DH parameters structure.
493 Represents a DSA public key using a B<SubjectPublicKeyInfo> structure.
495 =item B<DSAPublicKey>, B<DSAPrivateKey>
497 Use a non-standard OpenSSL format and should be avoided; use B<DSA_PUBKEY>,
498 L<PEM_write_PrivateKey(3)>, or similar instead.
502 Represents an ECDSA signature.
506 Represents an B<AlgorithmIdentifier> structure as used in IETF RFC 6960 and
511 Represents a B<Name> type as used for subject and issuer names in
512 IETF RFC 6960 and elsewhere.
516 Represents a PKCS#10 certificate request.
520 Represents the B<DigestInfo> structure defined in PKCS#1 and PKCS#7.
526 B<d2i_I<TYPE>>(), B<d2i_I<TYPE>_bio>() and B<d2i_I<TYPE>_fp>() return a valid
527 B<I<TYPE>> structure or NULL if an error occurs. If the "reuse" capability has
528 been used with a valid structure being passed in via I<a>, then the object is
529 freed in the event of error and I<*a> is set to NULL.
531 B<i2d_I<TYPE>>() returns the number of bytes successfully encoded or a negative
532 value if an error occurs.
534 B<i2d_I<TYPE>_bio>() and B<i2d_I<TYPE>_fp>() return 1 for success and 0 if an
539 Allocate and encode the DER encoding of an X509 structure:
545 len = i2d_X509(x, &buf);
549 Attempt to decode a buffer:
553 const unsigned char *p;
556 /* Set up buf and len to point to the input buffer. */
558 x = d2i_X509(NULL, &p, len);
562 Alternative technique:
566 const unsigned char *p;
569 /* Set up buf and len to point to the input buffer. */
573 if (d2i_X509(&x, &p, len) == NULL)
578 Using a temporary variable is mandatory. A common
579 mistake is to attempt to use a buffer directly as follows:
584 len = i2d_X509(x, NULL);
585 buf = OPENSSL_malloc(len);
591 This code will result in I<buf> apparently containing garbage because
592 it was incremented after the call to point after the data just written.
593 Also I<buf> will no longer contain the pointer allocated by OPENSSL_malloc()
594 and the subsequent call to OPENSSL_free() is likely to crash.
596 Another trap to avoid is misuse of the I<a> argument to B<d2i_I<TYPE>>():
600 if (d2i_X509(&x, &p, len) == NULL)
603 This will probably crash somewhere in d2i_X509(). The reason for this
604 is that the variable I<x> is uninitialized and an attempt will be made to
605 interpret its (invalid) value as an B<X509> structure, typically causing
606 a segmentation violation. If I<x> is set to NULL first then this will not
611 In some versions of OpenSSL the "reuse" behaviour of B<d2i_I<TYPE>>() when
612 I<*a> is valid is broken and some parts of the reused structure may
613 persist if they are not present in the new one. Additionally, in versions of
614 OpenSSL prior to 1.1.0, when the "reuse" behaviour is used and an error occurs
615 the behaviour is inconsistent. Some functions behaved as described here, while
616 some did not free I<*a> on error and did not set I<*a> to NULL.
618 As a result of the above issues the "reuse" behaviour is strongly discouraged.
620 B<i2d_I<TYPE>>() will not return an error in many versions of OpenSSL,
621 if mandatory fields are not initialized due to a programming error
622 then the encoded structure may contain invalid data or omit the
623 fields entirely and will not be parsed by B<d2i_I<TYPE>>(). This may be
624 fixed in future so code should not assume that B<i2d_I<TYPE>>() will
627 Any function which encodes a structure (B<i2d_I<TYPE>>(),
628 B<i2d_I<TYPE>>() or B<i2d_I<TYPE>>()) may return a stale encoding if the
629 structure has been modified after deserialization or previous
630 serialization. This is because some objects cache the encoding for
635 Copyright 1998-2020 The OpenSSL Project Authors. All Rights Reserved.
637 Licensed under the Apache License 2.0 (the "License"). You may not use
638 this file except in compliance with the License. You can obtain a copy
639 in the file LICENSE in the source distribution or at
640 L<https://www.openssl.org/source/license.html>.