5 d2i_ACCESS_DESCRIPTION,
7 d2i_ASIdentifierChoice,
12 d2i_ASN1_GENERALIZEDTIME,
13 d2i_ASN1_GENERALSTRING,
18 d2i_ASN1_OCTET_STRING,
20 d2i_ASN1_PRINTABLESTRING,
21 d2i_ASN1_SEQUENCE_ANY,
27 d2i_ASN1_UNIVERSALSTRING,
30 d2i_ASN1_VISIBLESTRING,
32 d2i_AUTHORITY_INFO_ACCESS,
34 d2i_BASIC_CONSTRAINTS,
35 d2i_CERTIFICATEPOLICIES,
37 d2i_CMS_ReceiptRequest,
46 d2i_DSAPrivateKey_bio,
63 d2i_ESS_ISSUER_SERIAL,
65 d2i_EXTENDED_KEY_USAGE,
72 d2i_ISSUING_DIST_POINT,
73 d2i_NETSCAPE_CERT_SEQUENCE,
105 d2i_PKCS7_ENC_CONTENT,
107 d2i_PKCS7_ISSUER_AND_SERIAL,
108 d2i_PKCS7_RECIP_INFO,
110 d2i_PKCS7_SIGNER_INFO,
111 d2i_PKCS7_SIGN_ENVELOPE,
114 d2i_PKCS8_PRIV_KEY_INFO,
115 d2i_PKCS8_PRIV_KEY_INFO_bio,
116 d2i_PKCS8_PRIV_KEY_INFO_fp,
119 d2i_PKEY_USAGE_PERIOD,
122 d2i_PROXY_CERT_INFO_EXTENSION,
126 d2i_RSAPrivateKey_bio,
127 d2i_RSAPrivateKey_fp,
129 d2i_RSAPublicKey_bio,
142 d2i_TS_MSG_IMPRINT_bio,
143 d2i_TS_MSG_IMPRINT_fp,
177 i2d_ACCESS_DESCRIPTION,
179 i2d_ASIdentifierChoice,
184 i2d_ASN1_GENERALIZEDTIME,
185 i2d_ASN1_GENERALSTRING,
190 i2d_ASN1_OCTET_STRING,
192 i2d_ASN1_PRINTABLESTRING,
193 i2d_ASN1_SEQUENCE_ANY,
198 i2d_ASN1_UNIVERSALSTRING,
201 i2d_ASN1_VISIBLESTRING,
204 i2d_AUTHORITY_INFO_ACCESS,
206 i2d_BASIC_CONSTRAINTS,
207 i2d_CERTIFICATEPOLICIES,
209 i2d_CMS_ReceiptRequest,
218 i2d_DSAPrivateKey_bio,
219 i2d_DSAPrivateKey_fp,
228 i2d_ECPrivateKey_bio,
235 i2d_ESS_ISSUER_SERIAL,
236 i2d_ESS_SIGNING_CERT,
237 i2d_EXTENDED_KEY_USAGE,
242 i2d_IPAddressOrRange,
244 i2d_ISSUING_DIST_POINT,
245 i2d_NETSCAPE_CERT_SEQUENCE,
260 i2d_OCSP_REVOKEDINFO,
277 i2d_PKCS7_ENC_CONTENT,
279 i2d_PKCS7_ISSUER_AND_SERIAL,
281 i2d_PKCS7_RECIP_INFO,
283 i2d_PKCS7_SIGNER_INFO,
284 i2d_PKCS7_SIGN_ENVELOPE,
287 i2d_PKCS8PrivateKeyInfo_bio,
288 i2d_PKCS8PrivateKeyInfo_fp,
289 i2d_PKCS8_PRIV_KEY_INFO,
290 i2d_PKCS8_PRIV_KEY_INFO_bio,
291 i2d_PKCS8_PRIV_KEY_INFO_fp,
294 i2d_PKEY_USAGE_PERIOD,
297 i2d_PROXY_CERT_INFO_EXTENSION,
301 i2d_RSAPrivateKey_bio,
302 i2d_RSAPrivateKey_fp,
304 i2d_RSAPublicKey_bio,
317 i2d_TS_MSG_IMPRINT_bio,
318 i2d_TS_MSG_IMPRINT_fp,
352 - convert objects from/to ASN.1/DER representation
358 TYPE *d2i_TYPE(TYPE **a, unsigned char **pp, long length);
359 TYPE *d2i_TYPE_bio(BIO *bp, TYPE **a);
360 TYPE *d2i_TYPE_fp(FILE *fp, TYPE **a);
362 int i2d_TYPE(TYPE *a, unsigned char **pp);
363 int i2d_TYPE_fp(FILE *fp, TYPE *a);
364 int i2d_TYPE_bio(BIO *bp, TYPE *a);
368 In the description here, I<TYPE> is used a placeholder
369 for any of the OpenSSL datatypes, such as I<X509_CRL>.
371 These functions convert OpenSSL objects to and from their ASN.1/DER
372 encoding. Unlike the C structures which can have pointers to sub-objects
373 within, the DER is a serialized encoding, suitable for sending over the
374 network, writing to a file, and so on.
376 d2i_TYPE() attempts to decode B<len> bytes at B<*in>. If successful a
377 pointer to the B<TYPE> structure is returned and B<*in> is incremented to
378 the byte following the parsed data. If B<a> is not B<NULL> then a pointer
379 to the returned structure is also written to B<*a>. If an error occurred
380 then B<NULL> is returned.
382 On a successful return, if B<*a> is not B<NULL> then it is assumed that B<*a>
383 contains a valid B<TYPE> structure and an attempt is made to reuse it. This
384 "reuse" capability is present for historical compatibility but its use is
385 B<strongly discouraged> (see BUGS below, and the discussion in the RETURN
388 d2i_TYPE_bio() is similar to d2i_TYPE() except it attempts
389 to parse data from BIO B<bp>.
391 d2i_TYPE_fp() is similar to d2i_TYPE() except it attempts
392 to parse data from FILE pointer B<fp>.
394 i2d_TYPE() encodes the structure pointed to by B<a> into DER format.
395 If B<out> is not B<NULL>, it writes the DER encoded data to the buffer
396 at B<*out>, and increments it to point after the data just written.
397 If the return value is negative an error occurred, otherwise it
398 returns the length of the encoded data.
400 If B<*out> is B<NULL> memory will be allocated for a buffer and the encoded
401 data written to it. In this case B<*out> is not incremented and it points
402 to the start of the data just written.
404 i2d_TYPE_bio() is similar to i2d_TYPE() except it writes
405 the encoding of the structure B<a> to BIO B<bp> and it
406 returns 1 for success and 0 for failure.
408 i2d_TYPE_fp() is similar to i2d_TYPE() except it writes
409 the encoding of the structure B<a> to BIO B<bp> and it
410 returns 1 for success and 0 for failure.
412 These routines do not encrypt private keys and therefore offer no
413 security; use L<PEM_write_PrivateKey(3)> or similar for writing to files.
417 The letters B<i> and B<d> in B<i2d_TYPE> stand for
418 "internal" (that is, an internal C structure) and "DER" respectively.
419 So B<i2d_TYPE> converts from internal to DER.
421 The functions can also understand B<BER> forms.
423 The actual TYPE structure passed to i2d_TYPE() must be a valid
424 populated B<TYPE> structure -- it B<cannot> simply be fed with an
425 empty structure such as that returned by TYPE_new().
427 The encoded data is in binary form and may contain embedded zeroes.
428 Therefore any FILE pointers or BIOs should be opened in binary mode.
429 Functions such as strlen() will B<not> return the correct length
430 of the encoded structure.
432 The ways that B<*in> and B<*out> are incremented after the operation
433 can trap the unwary. See the B<WARNINGS> section for some common
435 The reason for this-auto increment behaviour is to reflect a typical
436 usage of ASN1 functions: after one structure is encoded or decoded
437 another will be processed after it.
439 The following points about the data types might be useful:
445 Represents an ASN1 OBJECT IDENTIFIER.
449 Represents a PKCS#3 DH parameters structure.
453 Represents a ANSI X9.42 DH parameters structure.
457 Represents a DSA public key using a B<SubjectPublicKeyInfo> structure.
459 =item B<DSAPublicKey, DSAPrivateKey>
461 Use a non-standard OpenSSL format and should be avoided; use B<DSA_PUBKEY>,
462 B<PEM_write_PrivateKey(3)>, or similar instead.
464 =item B<RSAPublicKey>
466 Represents a PKCS#1 RSA public key structure.
470 Represents an B<AlgorithmIdentifier> structure as used in IETF RFC 6960 and
475 Represents a B<Name> type as used for subject and issuer names in
476 IETF RFC 6960 and elsewhere.
480 Represents a PKCS#10 certificate request.
484 Represents the B<DigestInfo> structure defined in PKCS#1 and PKCS#7.
490 Allocate and encode the DER encoding of an X509 structure:
496 len = i2d_X509(x, &buf);
500 Attempt to decode a buffer:
503 unsigned char *buf, *p;
506 /* Set up buf and len to point to the input buffer. */
508 x = d2i_X509(NULL, &p, len);
512 Alternative technique:
515 unsigned char *buf, *p;
518 /* Set up buf and len to point to the input buffer. */
522 if (d2i_X509(&x, &p, len) == NULL)
527 Using a temporary variable is mandatory. A common
528 mistake is to attempt to use a buffer directly as follows:
533 len = i2d_X509(x, NULL);
534 buf = OPENSSL_malloc(len);
540 This code will result in B<buf> apparently containing garbage because
541 it was incremented after the call to point after the data just written.
542 Also B<buf> will no longer contain the pointer allocated by OPENSSL_malloc()
543 and the subsequent call to OPENSSL_free() is likely to crash.
545 Another trap to avoid is misuse of the B<a> argument to d2i_TYPE():
549 if (d2i_X509(&x, &p, len) == NULL)
552 This will probably crash somewhere in d2i_X509(). The reason for this
553 is that the variable B<x> is uninitialized and an attempt will be made to
554 interpret its (invalid) value as an B<X509> structure, typically causing
555 a segmentation violation. If B<x> is set to NULL first then this will not
560 In some versions of OpenSSL the "reuse" behaviour of d2i_TYPE() when
561 B<*px> is valid is broken and some parts of the reused structure may
562 persist if they are not present in the new one. As a result the use
563 of this "reuse" behaviour is strongly discouraged.
565 i2d_TYPE() will not return an error in many versions of OpenSSL,
566 if mandatory fields are not initialized due to a programming error
567 then the encoded structure may contain invalid data or omit the
568 fields entirely and will not be parsed by d2i_TYPE(). This may be
569 fixed in future so code should not assume that i2d_TYPE() will
572 Any function which encodes a structure (i2d_TYPE(),
573 i2d_TYPE() or i2d_TYPE()) may return a stale encoding if the
574 structure has been modified after deserialization or previous
575 serialization. This is because some objects cache the encoding for
580 d2i_TYPE(), d2i_TYPE_bio() and d2i_TYPE_fp() return a valid B<TYPE> structure
581 or B<NULL> if an error occurs. If the "reuse" capability has been used with
582 a valid structure being passed in via B<a>, then the object is not freed in
583 the event of error but may be in a potentially invalid or inconsistent state.
585 i2d_TYPE() returns the number of bytes successfully encoded or a negative
586 value if an error occurs.
588 i2d_TYPE_bio() and i2d_TYPE_fp() return 1 for success and 0 if an error
593 Copyright 1998-2016 The OpenSSL Project Authors. All Rights Reserved.
595 Licensed under the OpenSSL license (the "License"). You may not use
596 this file except in compliance with the License. You can obtain a copy
597 in the file LICENSE in the source distribution or at
598 L<https://www.openssl.org/source/license.html>.