xref: /openssl/doc/man7/EVP_MAC-GMAC.pod (revision 8020d79b)
1=pod
2
3=head1 NAME
4
5EVP_MAC-GMAC - The GMAC EVP_MAC implementation
6
7=head1 DESCRIPTION
8
9Support for computing GMAC MACs through the B<EVP_MAC> API.
10
11This implementation uses EVP_CIPHER functions to get access to the underlying
12cipher.
13
14=head2 Identity
15
16This implementation is identified with this name and properties, to be
17used with EVP_MAC_fetch():
18
19=over 4
20
21=item "GMAC", "provider=default" or "provider=fips"
22
23=back
24
25=head2 Supported parameters
26
27The general description of these parameters can be found in
28L<EVP_MAC(3)/PARAMETERS>.
29
30The following parameter can be set with EVP_MAC_CTX_set_params():
31
32=over 4
33
34=item "key" (B<OSSL_MAC_PARAM_KEY>) <octet string>
35
36Sets the MAC key.
37Setting this parameter is identical to passing a I<key> to L<EVP_MAC_init(3)>.
38
39=item "iv" (B<OSSL_MAC_PARAM_IV>) <octet string>
40
41Sets the IV of the underlying cipher, when applicable.
42
43=item "cipher" (B<OSSL_MAC_PARAM_CIPHER>) <UTF8 string>
44
45Sets the name of the underlying cipher to be used.
46
47=item "properties" (B<OSSL_MAC_PARAM_PROPERTIES>) <UTF8 string>
48
49Sets the properties to be queried when trying to fetch the underlying cipher.
50This must be given together with the cipher naming parameter to be considered
51valid.
52
53=back
54
55The following parameters can be retrieved with
56EVP_MAC_CTX_get_params():
57
58=over 4
59
60=item "size" (B<OSSL_MAC_PARAM_SIZE>) <unsigned integer>
61
62Gets the MAC size.
63
64=back
65
66The "size" parameter can also be retrieved with EVP_MAC_CTX_get_mac_size().
67The length of the "size" parameter is equal to that of an B<unsigned int>.
68
69=head1 SEE ALSO
70
71L<EVP_MAC_CTX_get_params(3)>, L<EVP_MAC_CTX_set_params(3)>,
72L<EVP_MAC(3)/PARAMETERS>, L<OSSL_PARAM(3)>
73
74=head1 COPYRIGHT
75
76Copyright 2018-2021 The OpenSSL Project Authors. All Rights Reserved.
77
78Licensed under the Apache License 2.0 (the "License").  You may not use
79this file except in compliance with the License.  You can obtain a copy
80in the file LICENSE in the source distribution or at
81L<https://www.openssl.org/source/license.html>.
82
83=cut
84