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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(OCSP_CERTID *a, OCSP_CERTID *b);
 int OCSP_id_cmp(OCSP_CERTID *a, 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 non-zero
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(3)>,
L<OCSP_request_add1_nonce(3)>,
L<OCSP_REQUEST_new(3)>,
L<OCSP_response_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 OpenSSL license (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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