=pod

=head1 NAME

SSL_get_peer_signature_nid, SSL_get_peer_signature_type_nid,
SSL_get_signature_nid, SSL_get_signature_type_nid - get TLS message signing
types

=head1 SYNOPSIS

 #include <openssl/ssl.h>

 int SSL_get_peer_signature_nid(SSL *ssl, int *psig_nid);
 int SSL_get_peer_signature_type_nid(const SSL *ssl, int *psigtype_nid);
 int SSL_get_signature_nid(SSL *ssl, int *psig_nid);
 int SSL_get_signature_type_nid(const SSL *ssl, int *psigtype_nid);

=head1 DESCRIPTION

SSL_get_peer_signature_nid() sets B<*psig_nid> to the NID of the digest used
by the peer to sign TLS messages. It is implemented as a macro.

SSL_get_peer_signature_type_nid() sets B<*psigtype_nid> to the signature
type used by the peer to sign TLS messages. Currently the signature type
is the NID of the public key type used for signing except for PSS signing
where it is B<EVP_PKEY_RSA_PSS>. To differentiate between
B<rsa_pss_rsae_*> and B<rsa_pss_pss_*> signatures, it's necessary to check
the type of public key in the peer's certificate.

SSL_get_signature_nid() and SSL_get_signature_type_nid() return the equivalent
information for the local end of the connection.

=head1 RETURN VALUES

These functions return 1 for success and 0 for failure. There are several
possible reasons for failure: the cipher suite has no signature (e.g. it
uses RSA key exchange or is anonymous), the TLS version is below 1.2 or
the functions were called too early, e.g. before the peer signed a message.

=head1 SEE ALSO

L<ssl(7)>, L<SSL_get_peer_certificate(3)>,

=head1 COPYRIGHT

Copyright 2017-2018 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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