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=head1 NAME

OCSP_cert_to_id, OCSP_cert_id_new, OCSP_CERTID_free, OCSP_id_issuer_cmp,
OCSP_id_cmp, OCSP_id_get0_info - OCSP certificate ID utility functions

=head1 SYNOPSIS

 #include <openssl/ocsp.h>

 OCSP_CERTID *OCSP_cert_to_id(const EVP_MD *dgst,
                              X509 *subject, X509 *issuer);

 OCSP_CERTID *OCSP_cert_id_new(const EVP_MD *dgst,
                               X509_NAME *issuerName,
                               ASN1_BIT_STRING *issuerKey,
                               ASN1_INTEGER *serialNumber);

 void OCSP_CERTID_free(OCSP_CERTID *id);

 int OCSP_id_issuer_cmp(const OCSP_CERTID *a, const OCSP_CERTID *b);
 int OCSP_id_cmp(const OCSP_CERTID *a, const OCSP_CERTID *b);

 int OCSP_id_get0_info(ASN1_OCTET_STRING **piNameHash, ASN1_OBJECT **pmd,
                       ASN1_OCTET_STRING **pikeyHash,
                       ASN1_INTEGER **pserial, OCSP_CERTID *cid);


=head1 DESCRIPTION

OCSP_cert_to_id() creates and returns a new B<OCSP_CERTID> structure using
message digest B<dgst> for certificate B<subject> with issuer B<issuer>. If
B<dgst> is B<NULL> then SHA1 is used.

OCSP_cert_id_new() creates and returns a new B<OCSP_CERTID> using B<dgst> and
issuer name B<issuerName>, issuer key hash B<issuerKey> and serial number
B<serialNumber>.

OCSP_CERTID_free() frees up B<id>.

OCSP_id_cmp() compares B<OCSP_CERTID> B<a> and B<b>.

OCSP_id_issuer_cmp() compares only the issuer name of B<OCSP_CERTID> B<a> and B<b>.

OCSP_id_get0_info() returns the issuer name hash, hash OID, issuer key hash and
serial number contained in B<cid>. If any of the values are not required the
corresponding parameter can be set to B<NULL>.

=head1 RETURN VALUES

OCSP_cert_to_id() and OCSP_cert_id_new() return either a pointer to a valid
B<OCSP_CERTID> structure or B<NULL> if an error occurred.

OCSP_id_cmp() and OCSP_id_issuer_cmp() returns zero for a match and nonzero
otherwise.

OCSP_CERTID_free() does not return a value.

OCSP_id_get0_info() returns 1 for success and 0 for failure.

=head1 NOTES

OCSP clients will typically only use OCSP_cert_to_id() or OCSP_cert_id_new():
the other functions are used by responder applications.

The values returned by OCSP_id_get0_info() are internal pointers and B<MUST
NOT> be freed up by an application: they will be freed when the corresponding
B<OCSP_CERTID> structure is freed.

=head1 SEE ALSO

L<crypto(7)>,
L<OCSP_request_add1_nonce(3)>,
L<OCSP_REQUEST_new(3)>,
L<OCSP_resp_find_status(3)>,
L<OCSP_response_status(3)>,
L<OCSP_sendreq_new(3)>

=head1 COPYRIGHT

Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

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