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,
64 d2i_ESS_ISSUER_SERIAL,
66 d2i_EXTENDED_KEY_USAGE,
73 d2i_ISSUING_DIST_POINT,
74 d2i_NETSCAPE_CERT_SEQUENCE,
106 d2i_PKCS7_ENC_CONTENT,
108 d2i_PKCS7_ISSUER_AND_SERIAL,
109 d2i_PKCS7_RECIP_INFO,
111 d2i_PKCS7_SIGNER_INFO,
112 d2i_PKCS7_SIGN_ENVELOPE,
115 d2i_PKCS8_PRIV_KEY_INFO,
116 d2i_PKCS8_PRIV_KEY_INFO_bio,
117 d2i_PKCS8_PRIV_KEY_INFO_fp,
120 d2i_PKEY_USAGE_PERIOD,
123 d2i_PROXY_CERT_INFO_EXTENSION,
126 d2i_RSAPrivateKey_bio,
127 d2i_RSAPrivateKey_fp,
129 d2i_RSAPublicKey_bio,
141 d2i_TS_MSG_IMPRINT_bio,
142 d2i_TS_MSG_IMPRINT_fp,
176 i2d_ACCESS_DESCRIPTION,
178 i2d_ASIdentifierChoice,
183 i2d_ASN1_GENERALIZEDTIME,
184 i2d_ASN1_GENERALSTRING,
189 i2d_ASN1_OCTET_STRING,
191 i2d_ASN1_PRINTABLESTRING,
192 i2d_ASN1_SEQUENCE_ANY,
197 i2d_ASN1_UNIVERSALSTRING,
200 i2d_ASN1_VISIBLESTRING,
203 i2d_AUTHORITY_INFO_ACCESS,
205 i2d_BASIC_CONSTRAINTS,
206 i2d_CERTIFICATEPOLICIES,
208 i2d_CMS_ReceiptRequest,
217 i2d_DSAPrivateKey_bio,
218 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,
316 i2d_TS_MSG_IMPRINT_bio,
317 i2d_TS_MSG_IMPRINT_fp,
351 - convert objects from/to ASN.1/DER representation
357 TYPE *d2i_TYPE(TYPE **a, unsigned char **pp, long length);
358 TYPE *d2i_TYPE_bio(BIO *bp, TYPE **a);
359 TYPE *d2i_TYPE_fp(FILE *fp, TYPE **a);
361 int i2d_TYPE(TYPE *a, unsigned char **pp);
362 int i2d_TYPE_fp(FILE *fp, TYPE *a);
363 int i2d_TYPE_bio(BIO *bp, TYPE *a);
367 In the description here, I<TYPE> is used a placeholder
368 for any of the OpenSSL datatypes, such as I<X509_CRL>.
370 These functions convert OpenSSL objects to and from their ASN.1/DER
371 encoding. Unlike the C structures which can have pointers to sub-objects
372 within, the DER is a serialized encoding, suitable for sending over the
373 network, writing to a file, and so on.
375 d2i_TYPE() attempts to decode B<len> bytes at B<*in>. If successful a
376 pointer to the B<TYPE> structure is returned and B<*in> is incremented to
377 the byte following the parsed data. If B<a> is not B<NULL> then a pointer
378 to the returned structure is also written to B<*a>. If an error occurred
379 then B<NULL> is returned.
381 On a successful return, if B<*a> is not B<NULL> then it is assumed that B<*a>
382 contains a valid B<TYPE> structure and an attempt is made to reuse it. This
383 "reuse" capability is present for historical compatibility but its use is
384 B<strongly discouraged> (see BUGS below, and the discussion in the RETURN
387 d2i_TYPE_bio() is similar to d2i_TYPE() except it attempts
388 to parse data from BIO B<bp>.
390 d2i_TYPE_fp() is similar to d2i_TYPE() except it attempts
391 to parse data from FILE pointer B<fp>.
393 i2d_TYPE() encodes the structure pointed to by B<a> into DER format.
394 If B<out> is not B<NULL>, it writes the DER encoded data to the buffer
395 at B<*out>, and increments it to point after the data just written.
396 If the return value is negative an error occurred, otherwise it
397 returns the length of the encoded data.
399 If B<*out> is B<NULL> memory will be allocated for a buffer and the encoded
400 data written to it. In this case B<*out> is not incremented and it points
401 to the start of the data just written.
403 i2d_TYPE_bio() is similar to i2d_TYPE() except it writes
404 the encoding of the structure B<a> to BIO B<bp> and it
405 returns 1 for success and 0 for failure.
407 i2d_TYPE_fp() is similar to i2d_TYPE() except it writes
408 the encoding of the structure B<a> to BIO B<bp> and it
409 returns 1 for success and 0 for failure.
411 These routines do not encrypt private keys and therefore offer no
412 security; use L<PEM_write_PrivateKey(3)> or similar for writing to files.
416 The letters B<i> and B<d> in B<i2d_TYPE> stand for
417 "internal" (that is, an internal C structure) and "DER" respectively.
418 So B<i2d_TYPE> converts from internal to DER.
420 The functions can also understand B<BER> forms.
422 The actual TYPE structure passed to i2d_TYPE() must be a valid
423 populated B<TYPE> structure -- it B<cannot> simply be fed with an
424 empty structure such as that returned by TYPE_new().
426 The encoded data is in binary form and may contain embedded zeroes.
427 Therefore any FILE pointers or BIOs should be opened in binary mode.
428 Functions such as strlen() will B<not> return the correct length
429 of the encoded structure.
431 The ways that B<*in> and B<*out> are incremented after the operation
432 can trap the unwary. See the B<WARNINGS> section for some common
434 The reason for this-auto increment behaviour is to reflect a typical
435 usage of ASN1 functions: after one structure is encoded or decoded
436 another will be processed after it.
438 The following points about the data types might be useful:
444 Represents an ASN1 OBJECT IDENTIFIER.
448 Represents a PKCS#3 DH parameters structure.
452 Represents a ANSI X9.42 DH parameters structure.
456 Represents a DSA public key using a B<SubjectPublicKeyInfo> structure.
458 =item B<DSAPublicKey, DSAPrivateKey>
460 Use a non-standard OpenSSL format and should be avoided; use B<DSA_PUBKEY>,
461 B<PEM_write_PrivateKey(3)>, or similar instead.
463 =item B<RSAPublicKey>
465 Represents a PKCS#1 RSA public key structure.
469 Represents an B<AlgorithmIdentifier> structure as used in IETF RFC 6960 and
474 Represents a B<Name> type as used for subject and issuer names in
475 IETF RFC 6960 and elsewhere.
479 Represents a PKCS#10 certificate request.
483 Represents the B<DigestInfo> structure defined in PKCS#1 and PKCS#7.
489 Allocate and encode the DER encoding of an X509 structure:
495 len = i2d_X509(x, &buf);
499 Attempt to decode a buffer:
502 unsigned char *buf, *p;
505 /* Set up buf and len to point to the input buffer. */
507 x = d2i_X509(NULL, &p, len);
511 Alternative technique:
514 unsigned char *buf, *p;
517 /* Set up buf and len to point to the input buffer. */
521 if (d2i_X509(&x, &p, len) == NULL)
526 Using a temporary variable is mandatory. A common
527 mistake is to attempt to use a buffer directly as follows:
532 len = i2d_X509(x, NULL);
533 buf = OPENSSL_malloc(len);
539 This code will result in B<buf> apparently containing garbage because
540 it was incremented after the call to point after the data just written.
541 Also B<buf> will no longer contain the pointer allocated by OPENSSL_malloc()
542 and the subsequent call to OPENSSL_free() is likely to crash.
544 Another trap to avoid is misuse of the B<a> argument to d2i_TYPE():
548 if (d2i_X509(&x, &p, len) == NULL)
551 This will probably crash somewhere in d2i_X509(). The reason for this
552 is that the variable B<x> is uninitialized and an attempt will be made to
553 interpret its (invalid) value as an B<X509> structure, typically causing
554 a segmentation violation. If B<x> is set to NULL first then this will not
559 In some versions of OpenSSL the "reuse" behaviour of d2i_TYPE() when
560 B<*px> is valid is broken and some parts of the reused structure may
561 persist if they are not present in the new one. As a result the use
562 of this "reuse" behaviour is strongly discouraged.
564 i2d_TYPE() will not return an error in many versions of OpenSSL,
565 if mandatory fields are not initialized due to a programming error
566 then the encoded structure may contain invalid data or omit the
567 fields entirely and will not be parsed by d2i_TYPE(). This may be
568 fixed in future so code should not assume that i2d_TYPE() will
571 Any function which encodes a structure (i2d_TYPE(),
572 i2d_TYPE() or i2d_TYPE()) may return a stale encoding if the
573 structure has been modified after deserialization or previous
574 serialization. This is because some objects cache the encoding for
579 d2i_TYPE(), d2i_TYPE_bio() and d2i_TYPE_fp() return a valid B<TYPE> structure
580 or B<NULL> if an error occurs. If the "reuse" capability has been used with
581 a valid structure being passed in via B<a>, then the object is not freed in
582 the event of error but may be in a potentially invalid or inconsistent state.
584 i2d_TYPE() returns the number of bytes successfully encoded or a negative
585 value if an error occurs.
587 i2d_TYPE_bio() and i2d_TYPE_fp() return 1 for success and 0 if an error
592 Copyright 1998-2016 The OpenSSL Project Authors. All Rights Reserved.
594 Licensed under the OpenSSL license (the "License"). You may not use
595 this file except in compliance with the License. You can obtain a copy
596 in the file LICENSE in the source distribution or at
597 L<https://www.openssl.org/source/license.html>.