5 d2i_ACCESS_DESCRIPTION,
9 d2i_ASIdentifierChoice,
14 d2i_ASN1_GENERALIZEDTIME,
15 d2i_ASN1_GENERALSTRING,
20 d2i_ASN1_OCTET_STRING,
22 d2i_ASN1_PRINTABLESTRING,
23 d2i_ASN1_SEQUENCE_ANY,
29 d2i_ASN1_UNIVERSALSTRING,
32 d2i_ASN1_VISIBLESTRING,
34 d2i_AUTHORITY_INFO_ACCESS,
36 d2i_BASIC_CONSTRAINTS,
37 d2i_CERTIFICATEPOLICIES,
39 d2i_CMS_ReceiptRequest,
48 d2i_DSAPrivateKey_bio,
66 d2i_ESS_ISSUER_SERIAL,
68 d2i_EXTENDED_KEY_USAGE,
75 d2i_ISSUING_DIST_POINT,
77 d2i_NETSCAPE_CERT_SEQUENCE,
109 d2i_PKCS7_ENC_CONTENT,
111 d2i_PKCS7_ISSUER_AND_SERIAL,
112 d2i_PKCS7_RECIP_INFO,
114 d2i_PKCS7_SIGNER_INFO,
115 d2i_PKCS7_SIGN_ENVELOPE,
118 d2i_PKCS8_PRIV_KEY_INFO,
119 d2i_PKCS8_PRIV_KEY_INFO_bio,
120 d2i_PKCS8_PRIV_KEY_INFO_fp,
123 d2i_PKEY_USAGE_PERIOD,
127 d2i_PROXY_CERT_INFO_EXTENSION,
130 d2i_RSAPrivateKey_bio,
131 d2i_RSAPrivateKey_fp,
133 d2i_RSAPublicKey_bio,
146 d2i_TS_MSG_IMPRINT_bio,
147 d2i_TS_MSG_IMPRINT_fp,
181 i2d_ACCESS_DESCRIPTION,
183 i2d_ADMISSION_SYNTAX,
185 i2d_ASIdentifierChoice,
190 i2d_ASN1_GENERALIZEDTIME,
191 i2d_ASN1_GENERALSTRING,
196 i2d_ASN1_OCTET_STRING,
198 i2d_ASN1_PRINTABLESTRING,
199 i2d_ASN1_SEQUENCE_ANY,
204 i2d_ASN1_UNIVERSALSTRING,
207 i2d_ASN1_VISIBLESTRING,
210 i2d_AUTHORITY_INFO_ACCESS,
212 i2d_BASIC_CONSTRAINTS,
213 i2d_CERTIFICATEPOLICIES,
215 i2d_CMS_ReceiptRequest,
224 i2d_DSAPrivateKey_bio,
225 i2d_DSAPrivateKey_fp,
235 i2d_ECPrivateKey_bio,
242 i2d_ESS_ISSUER_SERIAL,
243 i2d_ESS_SIGNING_CERT,
244 i2d_EXTENDED_KEY_USAGE,
249 i2d_IPAddressOrRange,
251 i2d_ISSUING_DIST_POINT,
252 i2d_NAMING_AUTHORITY,
253 i2d_NETSCAPE_CERT_SEQUENCE,
268 i2d_OCSP_REVOKEDINFO,
285 i2d_PKCS7_ENC_CONTENT,
287 i2d_PKCS7_ISSUER_AND_SERIAL,
289 i2d_PKCS7_RECIP_INFO,
291 i2d_PKCS7_SIGNER_INFO,
292 i2d_PKCS7_SIGN_ENVELOPE,
295 i2d_PKCS8PrivateKeyInfo_bio,
296 i2d_PKCS8PrivateKeyInfo_fp,
297 i2d_PKCS8_PRIV_KEY_INFO,
298 i2d_PKCS8_PRIV_KEY_INFO_bio,
299 i2d_PKCS8_PRIV_KEY_INFO_fp,
302 i2d_PKEY_USAGE_PERIOD,
306 i2d_PROXY_CERT_INFO_EXTENSION,
310 i2d_RSAPrivateKey_bio,
311 i2d_RSAPrivateKey_fp,
313 i2d_RSAPublicKey_bio,
326 i2d_TS_MSG_IMPRINT_bio,
327 i2d_TS_MSG_IMPRINT_fp,
361 - convert objects from/to ASN.1/DER representation
367 TYPE *d2i_TYPE(TYPE **a, unsigned char **pp, long length);
368 TYPE *d2i_TYPE_bio(BIO *bp, TYPE **a);
369 TYPE *d2i_TYPE_fp(FILE *fp, TYPE **a);
371 int i2d_TYPE(TYPE *a, unsigned char **pp);
372 int i2d_TYPE_fp(FILE *fp, TYPE *a);
373 int i2d_TYPE_bio(BIO *bp, TYPE *a);
377 In the description here, I<TYPE> is used a placeholder
378 for any of the OpenSSL datatypes, such as I<X509_CRL>.
380 These functions convert OpenSSL objects to and from their ASN.1/DER
381 encoding. Unlike the C structures which can have pointers to sub-objects
382 within, the DER is a serialized encoding, suitable for sending over the
383 network, writing to a file, and so on.
385 d2i_TYPE() attempts to decode B<len> bytes at B<*in>. If successful a
386 pointer to the B<TYPE> structure is returned and B<*in> is incremented to
387 the byte following the parsed data. If B<a> is not B<NULL> then a pointer
388 to the returned structure is also written to B<*a>. If an error occurred
389 then B<NULL> is returned.
391 On a successful return, if B<*a> is not B<NULL> then it is assumed that B<*a>
392 contains a valid B<TYPE> structure and an attempt is made to reuse it. This
393 "reuse" capability is present for historical compatibility but its use is
394 B<strongly discouraged> (see BUGS below, and the discussion in the RETURN
397 d2i_TYPE_bio() is similar to d2i_TYPE() except it attempts
398 to parse data from BIO B<bp>.
400 d2i_TYPE_fp() is similar to d2i_TYPE() except it attempts
401 to parse data from FILE pointer B<fp>.
403 i2d_TYPE() encodes the structure pointed to by B<a> into DER format.
404 If B<out> is not B<NULL>, it writes the DER encoded data to the buffer
405 at B<*out>, and increments it to point after the data just written.
406 If the return value is negative an error occurred, otherwise it
407 returns the length of the encoded data.
409 If B<*out> is B<NULL> memory will be allocated for a buffer and the encoded
410 data written to it. In this case B<*out> is not incremented and it points
411 to the start of the data just written.
413 i2d_TYPE_bio() is similar to i2d_TYPE() except it writes
414 the encoding of the structure B<a> to BIO B<bp> and it
415 returns 1 for success and 0 for failure.
417 i2d_TYPE_fp() is similar to i2d_TYPE() except it writes
418 the encoding of the structure B<a> to BIO B<bp> and it
419 returns 1 for success and 0 for failure.
421 These routines do not encrypt private keys and therefore offer no
422 security; use L<PEM_write_PrivateKey(3)> or similar for writing to files.
426 The letters B<i> and B<d> in B<i2d_TYPE> stand for
427 "internal" (that is, an internal C structure) and "DER" respectively.
428 So B<i2d_TYPE> converts from internal to DER.
430 The functions can also understand B<BER> forms.
432 The actual TYPE structure passed to i2d_TYPE() must be a valid
433 populated B<TYPE> structure -- it B<cannot> simply be fed with an
434 empty structure such as that returned by TYPE_new().
436 The encoded data is in binary form and may contain embedded zeroes.
437 Therefore any FILE pointers or BIOs should be opened in binary mode.
438 Functions such as strlen() will B<not> return the correct length
439 of the encoded structure.
441 The ways that B<*in> and B<*out> are incremented after the operation
442 can trap the unwary. See the B<WARNINGS> section for some common
444 The reason for this-auto increment behaviour is to reflect a typical
445 usage of ASN1 functions: after one structure is encoded or decoded
446 another will be processed after it.
448 The following points about the data types might be useful:
454 Represents an ASN1 OBJECT IDENTIFIER.
458 Represents a PKCS#3 DH parameters structure.
462 Represents a ANSI X9.42 DH parameters structure.
466 Represents a DSA public key using a B<SubjectPublicKeyInfo> structure.
468 =item B<DSAPublicKey, DSAPrivateKey>
470 Use a non-standard OpenSSL format and should be avoided; use B<DSA_PUBKEY>,
471 B<PEM_write_PrivateKey(3)>, or similar instead.
473 =item B<RSAPublicKey>
475 Represents a PKCS#1 RSA public key structure.
479 Represents an B<AlgorithmIdentifier> structure as used in IETF RFC 6960 and
484 Represents a B<Name> type as used for subject and issuer names in
485 IETF RFC 6960 and elsewhere.
489 Represents a PKCS#10 certificate request.
493 Represents the B<DigestInfo> structure defined in PKCS#1 and PKCS#7.
499 Allocate and encode the DER encoding of an X509 structure:
505 len = i2d_X509(x, &buf);
509 Attempt to decode a buffer:
512 unsigned char *buf, *p;
515 /* Set up buf and len to point to the input buffer. */
517 x = d2i_X509(NULL, &p, len);
521 Alternative technique:
524 unsigned char *buf, *p;
527 /* Set up buf and len to point to the input buffer. */
531 if (d2i_X509(&x, &p, len) == NULL)
536 Using a temporary variable is mandatory. A common
537 mistake is to attempt to use a buffer directly as follows:
542 len = i2d_X509(x, NULL);
543 buf = OPENSSL_malloc(len);
549 This code will result in B<buf> apparently containing garbage because
550 it was incremented after the call to point after the data just written.
551 Also B<buf> will no longer contain the pointer allocated by OPENSSL_malloc()
552 and the subsequent call to OPENSSL_free() is likely to crash.
554 Another trap to avoid is misuse of the B<a> argument to d2i_TYPE():
558 if (d2i_X509(&x, &p, len) == NULL)
561 This will probably crash somewhere in d2i_X509(). The reason for this
562 is that the variable B<x> is uninitialized and an attempt will be made to
563 interpret its (invalid) value as an B<X509> structure, typically causing
564 a segmentation violation. If B<x> is set to NULL first then this will not
569 In some versions of OpenSSL the "reuse" behaviour of d2i_TYPE() when
570 B<*px> is valid is broken and some parts of the reused structure may
571 persist if they are not present in the new one. As a result the use
572 of this "reuse" behaviour is strongly discouraged.
574 i2d_TYPE() will not return an error in many versions of OpenSSL,
575 if mandatory fields are not initialized due to a programming error
576 then the encoded structure may contain invalid data or omit the
577 fields entirely and will not be parsed by d2i_TYPE(). This may be
578 fixed in future so code should not assume that i2d_TYPE() will
581 Any function which encodes a structure (i2d_TYPE(),
582 i2d_TYPE() or i2d_TYPE()) may return a stale encoding if the
583 structure has been modified after deserialization or previous
584 serialization. This is because some objects cache the encoding for
589 d2i_TYPE(), d2i_TYPE_bio() and d2i_TYPE_fp() return a valid B<TYPE> structure
590 or B<NULL> if an error occurs. If the "reuse" capability has been used with
591 a valid structure being passed in via B<a>, then the object is not freed in
592 the event of error but may be in a potentially invalid or inconsistent state.
594 i2d_TYPE() returns the number of bytes successfully encoded or a negative
595 value if an error occurs.
597 i2d_TYPE_bio() and i2d_TYPE_fp() return 1 for success and 0 if an error
602 Copyright 1998-2018 The OpenSSL Project Authors. All Rights Reserved.
604 Licensed under the OpenSSL license (the "License"). You may not use
605 this file except in compliance with the License. You can obtain a copy
606 in the file LICENSE in the source distribution or at
607 L<https://www.openssl.org/source/license.html>.