Latest update.

doc/man3/X509_get0_distinguishing_id.pod

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+=pod
+
+=head1 NAME
+
+X509_get0_distinguishing_id, X509_set0_distinguishing_id,
+X509_REQ_get0_distinguishing_id, X509_REQ_set0_distinguishing_id
+- get or set the Distinguishing ID for certificate operations
+
+=head1 SYNOPSIS
+
+ #include <openssl/x509.h>
+
+ ASN1_OCTET_STRING *X509_get0_distinguishing_id(X509 *x);
+ void X509_set0_distinguishing_id(X509 *x, ASN1_OCTET_STRING *distid);
+ ASN1_OCTET_STRING *X509_REQ_get0_distinguishing_id(X509_REQ *x);
+ void X509_REQ_set0_distinguishing_id(X509_REQ *x, ASN1_OCTET_STRING *distid);
+
+=head1 DESCRIPTION
+
+The Distinguishing ID is defined in FIPS 196 as follows:
+
+=over 4
+
+I<Distinguishing  identifier>: information which unambiguously distinguishes
+an entity in the authentication process.
+
+=back
+
+The SM2 signature algorithm requires a Distinguishing ID value when generating
+and verifying a signature, but the Ddistinguishing ID may also find other uses.
+In the context of SM2, the Distinguishing ID is often referred to as the "SM2
+ID".
+
+For the purpose off verifying a certificate or a certification request, a
+Distinguishing ID may be attached to it, so functions like L<X509_verify(3)>
+or L<X509_REQ_verify(3)> have easy access to that identity for signature
+verification.
+
+X509_get0_distinguishing_id() gets the Distinguishing ID value of a certificate
+B<x> by returning an B<ASN1_OCTET_STRING> object which should not be freed by
+the caller.
+
+X509_set0_distinguishing_id() assigns B<distid> to the certificate B<x>.
+Calling this function transfers the memory management of the value to the X509
+object, and therefore the value that has been passed in should not be freed by
+the caller after this function has been called.
+
+X509_REQ_get0_distinguishing_id() and X509_REQ_set0_distinguishing_id()
+have the same functionality as X509_get0_distinguishing_id() and
+X509_set0_distinguishing_id() except that they deal with  B<X509_REQ>
+objects instead of B<X509>.
+
+=head1 RETURN VALUES
+
+X509_set0_distinguishing_id() and X509_REQ_set0_distinguishing_id() do not
+return a value.
+
+=head1 SEE ALSO
+
+L<X509_verify(3)>, L<SM2(7)>
+
+=head1 COPYRIGHT
+
+Copyright 2019 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>.
+
+=cut