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 **ppin, 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 **ppout);
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>.
379 The function parameters I<ppin> and I<ppout> are generally
380 either both named I<pp> in the headers, or I<in> and I<out>.
382 These functions convert OpenSSL objects to and from their ASN.1/DER
383 encoding. Unlike the C structures which can have pointers to sub-objects
384 within, the DER is a serialized encoding, suitable for sending over the
385 network, writing to a file, and so on.
387 d2i_TYPE() attempts to decode B<len> bytes at B<*ppin>. If successful a
388 pointer to the B<TYPE> structure is returned and B<*ppin> is incremented to
389 the byte following the parsed data. If B<a> is not B<NULL> then a pointer
390 to the returned structure is also written to B<*a>. If an error occurred
391 then B<NULL> is returned.
393 On a successful return, if B<*a> is not B<NULL> then it is assumed that B<*a>
394 contains a valid B<TYPE> structure and an attempt is made to reuse it. This
395 "reuse" capability is present for historical compatibility but its use is
396 B<strongly discouraged> (see BUGS below, and the discussion in the RETURN
399 d2i_TYPE_bio() is similar to d2i_TYPE() except it attempts
400 to parse data from BIO B<bp>.
402 d2i_TYPE_fp() is similar to d2i_TYPE() except it attempts
403 to parse data from FILE pointer B<fp>.
405 i2d_TYPE() encodes the structure pointed to by B<a> into DER format.
406 If B<ppout> is not B<NULL>, it writes the DER encoded data to the buffer
407 at B<*ppout>, and increments it to point after the data just written.
408 If the return value is negative an error occurred, otherwise it
409 returns the length of the encoded data.
411 If B<*ppout> is B<NULL> memory will be allocated for a buffer and the encoded
412 data written to it. In this case B<*ppout> is not incremented and it points
413 to the start of the data just written.
415 i2d_TYPE_bio() is similar to i2d_TYPE() except it writes
416 the encoding of the structure B<a> to BIO B<bp> and it
417 returns 1 for success and 0 for failure.
419 i2d_TYPE_fp() is similar to i2d_TYPE() except it writes
420 the encoding of the structure B<a> to BIO B<bp> and it
421 returns 1 for success and 0 for failure.
423 These routines do not encrypt private keys and therefore offer no
424 security; use L<PEM_write_PrivateKey(3)> or similar for writing to files.
428 The letters B<i> and B<d> in B<i2d_TYPE> stand for
429 "internal" (that is, an internal C structure) and "DER" respectively.
430 So B<i2d_TYPE> converts from internal to DER.
432 The functions can also understand B<BER> forms.
434 The actual TYPE structure passed to i2d_TYPE() must be a valid
435 populated B<TYPE> structure -- it B<cannot> simply be fed with an
436 empty structure such as that returned by TYPE_new().
438 The encoded data is in binary form and may contain embedded zeroes.
439 Therefore any FILE pointers or BIOs should be opened in binary mode.
440 Functions such as strlen() will B<not> return the correct length
441 of the encoded structure.
443 The ways that B<*ppin> and B<*ppout> are incremented after the operation
444 can trap the unwary. See the B<WARNINGS> section for some common
446 The reason for this-auto increment behaviour is to reflect a typical
447 usage of ASN1 functions: after one structure is encoded or decoded
448 another will be processed after it.
450 The following points about the data types might be useful:
456 Represents an ASN1 OBJECT IDENTIFIER.
460 Represents a PKCS#3 DH parameters structure.
464 Represents an ANSI X9.42 DH parameters structure.
468 Represents a DSA public key using a B<SubjectPublicKeyInfo> structure.
470 =item B<DSAPublicKey, DSAPrivateKey>
472 Use a non-standard OpenSSL format and should be avoided; use B<DSA_PUBKEY>,
473 B<PEM_write_PrivateKey(3)>, or similar instead.
475 =item B<RSAPublicKey>
477 Represents a PKCS#1 RSA public key structure.
481 Represents an B<AlgorithmIdentifier> structure as used in IETF RFC 6960 and
486 Represents a B<Name> type as used for subject and issuer names in
487 IETF RFC 6960 and elsewhere.
491 Represents a PKCS#10 certificate request.
495 Represents the B<DigestInfo> structure defined in PKCS#1 and PKCS#7.
501 Allocate and encode the DER encoding of an X509 structure:
507 len = i2d_X509(x, &buf);
511 Attempt to decode a buffer:
514 unsigned char *buf, *p;
517 /* Set up buf and len to point to the input buffer. */
519 x = d2i_X509(NULL, &p, len);
523 Alternative technique:
526 unsigned char *buf, *p;
529 /* Set up buf and len to point to the input buffer. */
533 if (d2i_X509(&x, &p, len) == NULL)
538 Using a temporary variable is mandatory. A common
539 mistake is to attempt to use a buffer directly as follows:
544 len = i2d_X509(x, NULL);
545 buf = OPENSSL_malloc(len);
551 This code will result in B<buf> apparently containing garbage because
552 it was incremented after the call to point after the data just written.
553 Also B<buf> will no longer contain the pointer allocated by OPENSSL_malloc()
554 and the subsequent call to OPENSSL_free() is likely to crash.
556 Another trap to avoid is misuse of the B<a> argument to d2i_TYPE():
560 if (d2i_X509(&x, &p, len) == NULL)
563 This will probably crash somewhere in d2i_X509(). The reason for this
564 is that the variable B<x> is uninitialized and an attempt will be made to
565 interpret its (invalid) value as an B<X509> structure, typically causing
566 a segmentation violation. If B<x> is set to NULL first then this will not
571 In some versions of OpenSSL the "reuse" behaviour of d2i_TYPE() when
572 B<*px> is valid is broken and some parts of the reused structure may
573 persist if they are not present in the new one. As a result the use
574 of this "reuse" behaviour is strongly discouraged.
576 i2d_TYPE() will not return an error in many versions of OpenSSL,
577 if mandatory fields are not initialized due to a programming error
578 then the encoded structure may contain invalid data or omit the
579 fields entirely and will not be parsed by d2i_TYPE(). This may be
580 fixed in future so code should not assume that i2d_TYPE() will
583 Any function which encodes a structure (i2d_TYPE(),
584 i2d_TYPE() or i2d_TYPE()) may return a stale encoding if the
585 structure has been modified after deserialization or previous
586 serialization. This is because some objects cache the encoding for
591 d2i_TYPE(), d2i_TYPE_bio() and d2i_TYPE_fp() return a valid B<TYPE> structure
592 or B<NULL> if an error occurs. If the "reuse" capability has been used with
593 a valid structure being passed in via B<a>, then the object is not freed in
594 the event of error but may be in a potentially invalid or inconsistent state.
596 i2d_TYPE() returns the number of bytes successfully encoded or a negative
597 value if an error occurs.
599 i2d_TYPE_bio() and i2d_TYPE_fp() return 1 for success and 0 if an error
604 Copyright 1998-2018 The OpenSSL Project Authors. All Rights Reserved.
606 Licensed under the OpenSSL license (the "License"). You may not use
607 this file except in compliance with the License. You can obtain a copy
608 in the file LICENSE in the source distribution or at
609 L<https://www.openssl.org/source/license.html>.