1=pod 2 3=begin comment 4 5Any keypair function here that gets deprecated should be moved to 6d2i_RSAPrivateKey.pod. 7 8=end comment 9 10=head1 NAME 11 12d2i_ACCESS_DESCRIPTION, 13d2i_ADMISSIONS, 14d2i_ADMISSION_SYNTAX, 15d2i_ASIdOrRange, 16d2i_ASIdentifierChoice, 17d2i_ASIdentifiers, 18d2i_ASN1_BIT_STRING, 19d2i_ASN1_BMPSTRING, 20d2i_ASN1_ENUMERATED, 21d2i_ASN1_GENERALIZEDTIME, 22d2i_ASN1_GENERALSTRING, 23d2i_ASN1_IA5STRING, 24d2i_ASN1_INTEGER, 25d2i_ASN1_NULL, 26d2i_ASN1_OBJECT, 27d2i_ASN1_OCTET_STRING, 28d2i_ASN1_PRINTABLE, 29d2i_ASN1_PRINTABLESTRING, 30d2i_ASN1_SEQUENCE_ANY, 31d2i_ASN1_SET_ANY, 32d2i_ASN1_T61STRING, 33d2i_ASN1_TIME, 34d2i_ASN1_TYPE, 35d2i_ASN1_UINTEGER, 36d2i_ASN1_UNIVERSALSTRING, 37d2i_ASN1_UTCTIME, 38d2i_ASN1_UTF8STRING, 39d2i_ASN1_VISIBLESTRING, 40d2i_ASRange, 41d2i_AUTHORITY_INFO_ACCESS, 42d2i_AUTHORITY_KEYID, 43d2i_BASIC_CONSTRAINTS, 44d2i_CERTIFICATEPOLICIES, 45d2i_CMS_ContentInfo, 46d2i_CMS_ReceiptRequest, 47d2i_CMS_bio, 48d2i_CRL_DIST_POINTS, 49d2i_DHxparams, 50d2i_DIRECTORYSTRING, 51d2i_DISPLAYTEXT, 52d2i_DIST_POINT, 53d2i_DIST_POINT_NAME, 54d2i_DSA_SIG, 55d2i_ECDSA_SIG, 56d2i_ECPKParameters, 57d2i_EDIPARTYNAME, 58d2i_ESS_CERT_ID, 59d2i_ESS_CERT_ID_V2, 60d2i_ESS_ISSUER_SERIAL, 61d2i_ESS_SIGNING_CERT, 62d2i_ESS_SIGNING_CERT_V2, 63d2i_EXTENDED_KEY_USAGE, 64d2i_GENERAL_NAME, 65d2i_GENERAL_NAMES, 66d2i_IPAddressChoice, 67d2i_IPAddressFamily, 68d2i_IPAddressOrRange, 69d2i_IPAddressRange, 70d2i_ISSUER_SIGN_TOOL, 71d2i_ISSUING_DIST_POINT, 72d2i_NAMING_AUTHORITY, 73d2i_NETSCAPE_CERT_SEQUENCE, 74d2i_NETSCAPE_SPKAC, 75d2i_NETSCAPE_SPKI, 76d2i_NOTICEREF, 77d2i_OCSP_BASICRESP, 78d2i_OCSP_CERTID, 79d2i_OCSP_CERTSTATUS, 80d2i_OCSP_CRLID, 81d2i_OCSP_ONEREQ, 82d2i_OCSP_REQINFO, 83d2i_OCSP_REQUEST, 84d2i_OCSP_RESPBYTES, 85d2i_OCSP_RESPDATA, 86d2i_OCSP_RESPID, 87d2i_OCSP_RESPONSE, 88d2i_OCSP_REVOKEDINFO, 89d2i_OCSP_SERVICELOC, 90d2i_OCSP_SIGNATURE, 91d2i_OCSP_SINGLERESP, 92d2i_OSSL_CMP_MSG, 93d2i_OSSL_CMP_PKIHEADER, 94d2i_OSSL_CMP_PKISI, 95d2i_OSSL_CRMF_CERTID, 96d2i_OSSL_CRMF_CERTTEMPLATE, 97d2i_OSSL_CRMF_ENCRYPTEDVALUE, 98d2i_OSSL_CRMF_MSG, 99d2i_OSSL_CRMF_MSGS, 100d2i_OSSL_CRMF_PBMPARAMETER, 101d2i_OSSL_CRMF_PKIPUBLICATIONINFO, 102d2i_OSSL_CRMF_SINGLEPUBINFO, 103d2i_OTHERNAME, 104d2i_PBE2PARAM, 105d2i_PBEPARAM, 106d2i_PBKDF2PARAM, 107d2i_PKCS12, 108d2i_PKCS12_BAGS, 109d2i_PKCS12_MAC_DATA, 110d2i_PKCS12_SAFEBAG, 111d2i_PKCS12_bio, 112d2i_PKCS12_fp, 113d2i_PKCS7, 114d2i_PKCS7_DIGEST, 115d2i_PKCS7_ENCRYPT, 116d2i_PKCS7_ENC_CONTENT, 117d2i_PKCS7_ENVELOPE, 118d2i_PKCS7_ISSUER_AND_SERIAL, 119d2i_PKCS7_RECIP_INFO, 120d2i_PKCS7_SIGNED, 121d2i_PKCS7_SIGNER_INFO, 122d2i_PKCS7_SIGN_ENVELOPE, 123d2i_PKCS7_bio, 124d2i_PKCS7_fp, 125d2i_PKCS8_PRIV_KEY_INFO, 126d2i_PKCS8_PRIV_KEY_INFO_bio, 127d2i_PKCS8_PRIV_KEY_INFO_fp, 128d2i_PKCS8_bio, 129d2i_PKCS8_fp, 130d2i_PKEY_USAGE_PERIOD, 131d2i_POLICYINFO, 132d2i_POLICYQUALINFO, 133d2i_PROFESSION_INFO, 134d2i_PROXY_CERT_INFO_EXTENSION, 135d2i_PROXY_POLICY, 136d2i_RSA_OAEP_PARAMS, 137d2i_RSA_PSS_PARAMS, 138d2i_SCRYPT_PARAMS, 139d2i_SCT_LIST, 140d2i_SXNET, 141d2i_SXNETID, 142d2i_TS_ACCURACY, 143d2i_TS_MSG_IMPRINT, 144d2i_TS_MSG_IMPRINT_bio, 145d2i_TS_MSG_IMPRINT_fp, 146d2i_TS_REQ, 147d2i_TS_REQ_bio, 148d2i_TS_REQ_fp, 149d2i_TS_RESP, 150d2i_TS_RESP_bio, 151d2i_TS_RESP_fp, 152d2i_TS_STATUS_INFO, 153d2i_TS_TST_INFO, 154d2i_TS_TST_INFO_bio, 155d2i_TS_TST_INFO_fp, 156d2i_USERNOTICE, 157d2i_X509, 158d2i_X509_bio, 159d2i_X509_fp, 160d2i_X509_ALGOR, 161d2i_X509_ALGORS, 162d2i_X509_ATTRIBUTE, 163d2i_X509_CERT_AUX, 164d2i_X509_CINF, 165d2i_X509_CRL, 166d2i_X509_CRL_INFO, 167d2i_X509_CRL_bio, 168d2i_X509_CRL_fp, 169d2i_X509_EXTENSION, 170d2i_X509_EXTENSIONS, 171d2i_X509_NAME, 172d2i_X509_NAME_ENTRY, 173d2i_X509_PUBKEY, 174d2i_X509_PUBKEY_bio, 175d2i_X509_PUBKEY_fp, 176d2i_X509_REQ, 177d2i_X509_REQ_INFO, 178d2i_X509_REQ_bio, 179d2i_X509_REQ_fp, 180d2i_X509_REVOKED, 181d2i_X509_SIG, 182d2i_X509_VAL, 183i2d_ACCESS_DESCRIPTION, 184i2d_ADMISSIONS, 185i2d_ADMISSION_SYNTAX, 186i2d_ASIdOrRange, 187i2d_ASIdentifierChoice, 188i2d_ASIdentifiers, 189i2d_ASN1_BIT_STRING, 190i2d_ASN1_BMPSTRING, 191i2d_ASN1_ENUMERATED, 192i2d_ASN1_GENERALIZEDTIME, 193i2d_ASN1_GENERALSTRING, 194i2d_ASN1_IA5STRING, 195i2d_ASN1_INTEGER, 196i2d_ASN1_NULL, 197i2d_ASN1_OBJECT, 198i2d_ASN1_OCTET_STRING, 199i2d_ASN1_PRINTABLE, 200i2d_ASN1_PRINTABLESTRING, 201i2d_ASN1_SEQUENCE_ANY, 202i2d_ASN1_SET_ANY, 203i2d_ASN1_T61STRING, 204i2d_ASN1_TIME, 205i2d_ASN1_TYPE, 206i2d_ASN1_UNIVERSALSTRING, 207i2d_ASN1_UTCTIME, 208i2d_ASN1_UTF8STRING, 209i2d_ASN1_VISIBLESTRING, 210i2d_ASN1_bio_stream, 211i2d_ASRange, 212i2d_AUTHORITY_INFO_ACCESS, 213i2d_AUTHORITY_KEYID, 214i2d_BASIC_CONSTRAINTS, 215i2d_CERTIFICATEPOLICIES, 216i2d_CMS_ContentInfo, 217i2d_CMS_ReceiptRequest, 218i2d_CMS_bio, 219i2d_CRL_DIST_POINTS, 220i2d_DHxparams, 221i2d_DIRECTORYSTRING, 222i2d_DISPLAYTEXT, 223i2d_DIST_POINT, 224i2d_DIST_POINT_NAME, 225i2d_DSA_SIG, 226i2d_ECDSA_SIG, 227i2d_ECPKParameters, 228i2d_EDIPARTYNAME, 229i2d_ESS_CERT_ID, 230i2d_ESS_CERT_ID_V2, 231i2d_ESS_ISSUER_SERIAL, 232i2d_ESS_SIGNING_CERT, 233i2d_ESS_SIGNING_CERT_V2, 234i2d_EXTENDED_KEY_USAGE, 235i2d_GENERAL_NAME, 236i2d_GENERAL_NAMES, 237i2d_IPAddressChoice, 238i2d_IPAddressFamily, 239i2d_IPAddressOrRange, 240i2d_IPAddressRange, 241i2d_ISSUER_SIGN_TOOL, 242i2d_ISSUING_DIST_POINT, 243i2d_NAMING_AUTHORITY, 244i2d_NETSCAPE_CERT_SEQUENCE, 245i2d_NETSCAPE_SPKAC, 246i2d_NETSCAPE_SPKI, 247i2d_NOTICEREF, 248i2d_OCSP_BASICRESP, 249i2d_OCSP_CERTID, 250i2d_OCSP_CERTSTATUS, 251i2d_OCSP_CRLID, 252i2d_OCSP_ONEREQ, 253i2d_OCSP_REQINFO, 254i2d_OCSP_REQUEST, 255i2d_OCSP_RESPBYTES, 256i2d_OCSP_RESPDATA, 257i2d_OCSP_RESPID, 258i2d_OCSP_RESPONSE, 259i2d_OCSP_REVOKEDINFO, 260i2d_OCSP_SERVICELOC, 261i2d_OCSP_SIGNATURE, 262i2d_OCSP_SINGLERESP, 263i2d_OSSL_CMP_MSG, 264i2d_OSSL_CMP_PKIHEADER, 265i2d_OSSL_CMP_PKISI, 266i2d_OSSL_CRMF_CERTID, 267i2d_OSSL_CRMF_CERTTEMPLATE, 268i2d_OSSL_CRMF_ENCRYPTEDVALUE, 269i2d_OSSL_CRMF_MSG, 270i2d_OSSL_CRMF_MSGS, 271i2d_OSSL_CRMF_PBMPARAMETER, 272i2d_OSSL_CRMF_PKIPUBLICATIONINFO, 273i2d_OSSL_CRMF_SINGLEPUBINFO, 274i2d_OTHERNAME, 275i2d_PBE2PARAM, 276i2d_PBEPARAM, 277i2d_PBKDF2PARAM, 278i2d_PKCS12, 279i2d_PKCS12_BAGS, 280i2d_PKCS12_MAC_DATA, 281i2d_PKCS12_SAFEBAG, 282i2d_PKCS12_bio, 283i2d_PKCS12_fp, 284i2d_PKCS7, 285i2d_PKCS7_DIGEST, 286i2d_PKCS7_ENCRYPT, 287i2d_PKCS7_ENC_CONTENT, 288i2d_PKCS7_ENVELOPE, 289i2d_PKCS7_ISSUER_AND_SERIAL, 290i2d_PKCS7_NDEF, 291i2d_PKCS7_RECIP_INFO, 292i2d_PKCS7_SIGNED, 293i2d_PKCS7_SIGNER_INFO, 294i2d_PKCS7_SIGN_ENVELOPE, 295i2d_PKCS7_bio, 296i2d_PKCS7_fp, 297i2d_PKCS8PrivateKeyInfo_bio, 298i2d_PKCS8PrivateKeyInfo_fp, 299i2d_PKCS8_PRIV_KEY_INFO, 300i2d_PKCS8_PRIV_KEY_INFO_bio, 301i2d_PKCS8_PRIV_KEY_INFO_fp, 302i2d_PKCS8_bio, 303i2d_PKCS8_fp, 304i2d_PKEY_USAGE_PERIOD, 305i2d_POLICYINFO, 306i2d_POLICYQUALINFO, 307i2d_PROFESSION_INFO, 308i2d_PROXY_CERT_INFO_EXTENSION, 309i2d_PROXY_POLICY, 310i2d_RSA_OAEP_PARAMS, 311i2d_RSA_PSS_PARAMS, 312i2d_SCRYPT_PARAMS, 313i2d_SCT_LIST, 314i2d_SXNET, 315i2d_SXNETID, 316i2d_TS_ACCURACY, 317i2d_TS_MSG_IMPRINT, 318i2d_TS_MSG_IMPRINT_bio, 319i2d_TS_MSG_IMPRINT_fp, 320i2d_TS_REQ, 321i2d_TS_REQ_bio, 322i2d_TS_REQ_fp, 323i2d_TS_RESP, 324i2d_TS_RESP_bio, 325i2d_TS_RESP_fp, 326i2d_TS_STATUS_INFO, 327i2d_TS_TST_INFO, 328i2d_TS_TST_INFO_bio, 329i2d_TS_TST_INFO_fp, 330i2d_USERNOTICE, 331i2d_X509, 332i2d_X509_bio, 333i2d_X509_fp, 334i2d_X509_ALGOR, 335i2d_X509_ALGORS, 336i2d_X509_ATTRIBUTE, 337i2d_X509_CERT_AUX, 338i2d_X509_CINF, 339i2d_X509_CRL, 340i2d_X509_CRL_INFO, 341i2d_X509_CRL_bio, 342i2d_X509_CRL_fp, 343i2d_X509_EXTENSION, 344i2d_X509_EXTENSIONS, 345i2d_X509_NAME, 346i2d_X509_NAME_ENTRY, 347i2d_X509_PUBKEY, 348i2d_X509_PUBKEY_bio, 349i2d_X509_PUBKEY_fp, 350i2d_X509_REQ, 351i2d_X509_REQ_INFO, 352i2d_X509_REQ_bio, 353i2d_X509_REQ_fp, 354i2d_X509_REVOKED, 355i2d_X509_SIG, 356i2d_X509_VAL, 357- convert objects from/to ASN.1/DER representation 358 359=head1 SYNOPSIS 360 361=for openssl generic 362 363 TYPE *d2i_TYPE(TYPE **a, const unsigned char **ppin, long length); 364 TYPE *d2i_TYPE_bio(BIO *bp, TYPE **a); 365 TYPE *d2i_TYPE_fp(FILE *fp, TYPE **a); 366 367 int i2d_TYPE(const TYPE *a, unsigned char **ppout); 368 int i2d_TYPE(TYPE *a, unsigned char **ppout); 369 int i2d_TYPE_fp(FILE *fp, const TYPE *a); 370 int i2d_TYPE_fp(FILE *fp, TYPE *a); 371 int i2d_TYPE_bio(BIO *bp, const TYPE *a); 372 int i2d_TYPE_bio(BIO *bp, TYPE *a); 373 374=head1 DESCRIPTION 375 376In the description here, B<I<TYPE>> is used a placeholder 377for any of the OpenSSL datatypes, such as B<X509_CRL>. 378The function parameters I<ppin> and I<ppout> are generally 379either both named I<pp> in the headers, or I<in> and I<out>. 380 381These functions convert OpenSSL objects to and from their ASN.1/DER 382encoding. Unlike the C structures which can have pointers to sub-objects 383within, the DER is a serialized encoding, suitable for sending over the 384network, writing to a file, and so on. 385 386B<d2i_I<TYPE>>() attempts to decode I<len> bytes at I<*ppin>. If successful a 387pointer to the B<I<TYPE>> structure is returned and I<*ppin> is incremented to 388the byte following the parsed data. If I<a> is not NULL then a pointer 389to the returned structure is also written to I<*a>. If an error occurred 390then NULL is returned. 391 392On a successful return, if I<*a> is not NULL then it is assumed that I<*a> 393contains a valid B<I<TYPE>> structure and an attempt is made to reuse it. 394For B<I<TYPE>> structures where it matters it is possible to set up a library 395context on the decoded structure this way (see the B<EXAMPLES> section). 396However using the "reuse" capability for other purposes is B<strongly 397discouraged> (see B<BUGS> below, and the discussion in the B<RETURN VALUES> 398section). 399 400B<d2i_I<TYPE>_bio>() is similar to B<d2i_I<TYPE>>() except it attempts 401to parse data from BIO I<bp>. 402 403B<d2i_I<TYPE>_fp>() is similar to B<d2i_I<TYPE>>() except it attempts 404to parse data from FILE pointer I<fp>. 405 406B<i2d_I<TYPE>>() encodes the structure pointed to by I<a> into DER format. 407If I<ppout> is not NULL, it writes the DER encoded data to the buffer 408at I<*ppout>, and increments it to point after the data just written. 409If the return value is negative an error occurred, otherwise it 410returns the length of the encoded data. 411 412If I<*ppout> is NULL memory will be allocated for a buffer and the encoded 413data written to it. In this case I<*ppout> is not incremented and it points 414to the start of the data just written. 415 416B<i2d_I<TYPE>_bio>() is similar to B<i2d_I<TYPE>>() except it writes 417the encoding of the structure I<a> to BIO I<bp> and it 418returns 1 for success and 0 for failure. 419 420B<i2d_I<TYPE>_fp>() is similar to B<i2d_I<TYPE>>() except it writes 421the encoding of the structure I<a> to FILE pointer I<fp> and it 422returns 1 for success and 0 for failure. 423 424These routines do not encrypt private keys and therefore offer no 425security; use L<PEM_write_PrivateKey(3)> or similar for writing to files. 426 427=head1 NOTES 428 429The letters B<i> and B<d> in B<i2d_I<TYPE>>() stand for 430"internal" (that is, an internal C structure) and "DER" respectively. 431So B<i2d_I<TYPE>>() converts from internal to DER. 432 433The functions can also understand B<BER> forms. 434 435The actual TYPE structure passed to B<i2d_I<TYPE>>() must be a valid 436populated B<I<TYPE>> structure -- it B<cannot> simply be fed with an 437empty structure such as that returned by TYPE_new(). 438 439The encoded data is in binary form and may contain embedded zeros. 440Therefore, any FILE pointers or BIOs should be opened in binary mode. 441Functions such as strlen() will B<not> return the correct length 442of the encoded structure. 443 444The ways that I<*ppin> and I<*ppout> are incremented after the operation 445can trap the unwary. See the B<WARNINGS> section for some common 446errors. 447The reason for this-auto increment behaviour is to reflect a typical 448usage of ASN1 functions: after one structure is encoded or decoded 449another will be processed after it. 450 451The following points about the data types might be useful: 452 453=over 4 454 455=item B<ASN1_OBJECT> 456 457Represents an ASN1 OBJECT IDENTIFIER. 458 459=item B<DHparams> 460 461Represents a PKCS#3 DH parameters structure. 462 463=item B<DHxparams> 464 465Represents an ANSI X9.42 DH parameters structure. 466 467=item B<ECDSA_SIG> 468 469Represents an ECDSA signature. 470 471=item B<X509_ALGOR> 472 473Represents an B<AlgorithmIdentifier> structure as used in IETF RFC 6960 and 474elsewhere. 475 476=item B<X509_NAME> 477 478Represents a B<Name> type as used for subject and issuer names in 479IETF RFC 6960 and elsewhere. 480 481=item B<X509_REQ> 482 483Represents a PKCS#10 certificate request. 484 485=item B<X509_SIG> 486 487Represents the B<DigestInfo> structure defined in PKCS#1 and PKCS#7. 488 489=back 490 491=head1 RETURN VALUES 492 493B<d2i_I<TYPE>>(), B<d2i_I<TYPE>_bio>() and B<d2i_I<TYPE>_fp>() return a valid 494B<I<TYPE>> structure or NULL if an error occurs. If the "reuse" capability has 495been used with a valid structure being passed in via I<a>, then the object is 496freed in the event of error and I<*a> is set to NULL. 497 498B<i2d_I<TYPE>>() returns the number of bytes successfully encoded or a negative 499value if an error occurs. 500 501B<i2d_I<TYPE>_bio>() and B<i2d_I<TYPE>_fp>() return 1 for success and 0 if an 502error occurs. 503 504=head1 EXAMPLES 505 506Allocate and encode the DER encoding of an X509 structure: 507 508 int len; 509 unsigned char *buf; 510 511 buf = NULL; 512 len = i2d_X509(x, &buf); 513 if (len < 0) 514 /* error */ 515 516Attempt to decode a buffer: 517 518 X509 *x; 519 unsigned char *buf; 520 const unsigned char *p; 521 int len; 522 523 /* Set up buf and len to point to the input buffer. */ 524 p = buf; 525 x = d2i_X509(NULL, &p, len); 526 if (x == NULL) 527 /* error */ 528 529Alternative technique: 530 531 X509 *x; 532 unsigned char *buf; 533 const unsigned char *p; 534 int len; 535 536 /* Set up buf and len to point to the input buffer. */ 537 p = buf; 538 x = NULL; 539 540 if (d2i_X509(&x, &p, len) == NULL) 541 /* error */ 542 543Setting up a library context and property query: 544 545 X509 *x; 546 unsigned char *buf; 547 const unsigned char *p; 548 int len; 549 OSSL_LIB_CTX *libctx = ....; 550 const char *propq = ....; 551 552 /* Set up buf and len to point to the input buffer. */ 553 p = buf; 554 x = X509_new_ex(libctx, propq); 555 556 if (d2i_X509(&x, &p, len) == NULL) 557 /* error, x was freed and NULL assigned to it (see RETURN VALUES) */ 558 559=head1 WARNINGS 560 561Using a temporary variable is mandatory. A common 562mistake is to attempt to use a buffer directly as follows: 563 564 int len; 565 unsigned char *buf; 566 567 len = i2d_X509(x, NULL); 568 buf = OPENSSL_malloc(len); 569 ... 570 i2d_X509(x, &buf); 571 ... 572 OPENSSL_free(buf); 573 574This code will result in I<buf> apparently containing garbage because 575it was incremented after the call to point after the data just written. 576Also I<buf> will no longer contain the pointer allocated by OPENSSL_malloc() 577and the subsequent call to OPENSSL_free() is likely to crash. 578 579Another trap to avoid is misuse of the I<a> argument to B<d2i_I<TYPE>>(): 580 581 X509 *x; 582 583 if (d2i_X509(&x, &p, len) == NULL) 584 /* error */ 585 586This will probably crash somewhere in d2i_X509(). The reason for this 587is that the variable I<x> is uninitialized and an attempt will be made to 588interpret its (invalid) value as an B<X509> structure, typically causing 589a segmentation violation. If I<x> is set to NULL first then this will not 590happen. 591 592=head1 BUGS 593 594In some versions of OpenSSL the "reuse" behaviour of B<d2i_I<TYPE>>() when 595I<*a> is valid is broken and some parts of the reused structure may 596persist if they are not present in the new one. Additionally, in versions of 597OpenSSL prior to 1.1.0, when the "reuse" behaviour is used and an error occurs 598the behaviour is inconsistent. Some functions behaved as described here, while 599some did not free I<*a> on error and did not set I<*a> to NULL. 600 601As a result of the above issues the "reuse" behaviour is strongly discouraged. 602 603B<i2d_I<TYPE>>() will not return an error in many versions of OpenSSL, 604if mandatory fields are not initialized due to a programming error 605then the encoded structure may contain invalid data or omit the 606fields entirely and will not be parsed by B<d2i_I<TYPE>>(). This may be 607fixed in future so code should not assume that B<i2d_I<TYPE>>() will 608always succeed. 609 610Any function which encodes a structure (B<i2d_I<TYPE>>(), 611B<i2d_I<TYPE>_bio>() or B<i2d_I<TYPE>_fp>()) may return a stale encoding if the 612structure has been modified after deserialization or previous 613serialization. This is because some objects cache the encoding for 614efficiency reasons. 615 616=head1 COPYRIGHT 617 618Copyright 1998-2023 The OpenSSL Project Authors. All Rights Reserved. 619 620Licensed under the Apache License 2.0 (the "License"). You may not use 621this file except in compliance with the License. You can obtain a copy 622in the file LICENSE in the source distribution or at 623L<https://www.openssl.org/source/license.html>. 624 625=cut 626