5 EVP_MAC-KMAC, EVP_MAC-KMAC128, EVP_MAC-KMAC256
6 - The KMAC EVP_MAC implementations
10 Support for computing KMAC MACs through the B<EVP_MAC> API.
14 These implementations are identified with one of these names and
15 properties, to be used with EVP_MAC_fetch():
19 =item "KMAC-128", "provider=default" or "provider=fips"
21 =item "KMAC-256", "provider=default" or "provider=fips"
25 =head2 Supported parameters
27 The general description of these parameters can be found in
28 L<EVP_MAC(3)/PARAMETERS>.
30 All these parameters can be set with EVP_MAC_CTX_set_params().
31 Furthermore, the "size" parameter can be retrieved with
32 EVP_MAC_CTX_get_params(), or with EVP_MAC_CTX_get_mac_size().
33 The length of the "size" parameter should not exceed that of a B<size_t>.
37 =item "key" (B<OSSL_MAC_PARAM_KEY>) <octet string>
40 Setting this parameter is identical to passing a I<key> to L<EVP_MAC_init(3)>.
42 =item "custom" (B<OSSL_MAC_PARAM_CUSTOM>) <octet string>
44 Sets the custom value.
45 It is an optional value of at most 127 bytes, and is empty by default.
47 =item "size" (B<OSSL_MAC_PARAM_SIZE>) <unsigned integer>
50 By default, it is 16 for C<KMAC-128> and 32 for C<KMAC-256>.
52 =item "xof" (B<OSSL_MAC_PARAM_XOF>) <integer>
54 The "xof" parameter value is expected to be 1 or 0. Use 1 to enable XOF mode.
55 The default value is 0.
59 The "custom" parameter must be set as part of or before the EVP_MAC_init() call.
60 The "xof" and "size" parameters can be set at any time before EVP_MAC_final().
61 The "key" parameter is set as part of the EVP_MAC_init() call, but can be
62 set before it instead.
66 #include <openssl/evp.h>
67 #include <openssl/params.h>
69 static int do_kmac(const unsigned char *in, size_t in_len,
70 const unsigned char *key, size_t key_len,
71 const unsigned char *custom, size_t custom_len,
72 int xof_enabled, unsigned char *out, int out_len)
74 EVP_MAC_CTX *ctx = NULL;
76 OSSL_PARAM params[4], *p;
80 mac = EVP_MAC_fetch(NULL, "KMAC-128", NULL);
83 ctx = EVP_MAC_CTX_new(mac);
84 /* The mac can be freed after it is used by EVP_MAC_CTX_new */
90 * Setup parameters required before calling EVP_MAC_init()
91 * The parameters OSSL_MAC_PARAM_XOF and OSSL_MAC_PARAM_SIZE may also be
95 *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
96 (void *)key, key_len);
97 if (custom != NULL && custom_len != 0)
98 *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_CUSTOM,
99 (void *)custom, custom_len);
100 *p = OSSL_PARAM_construct_end();
101 if (!EVP_MAC_CTX_set_params(ctx, params))
104 if (!EVP_MAC_init(ctx))
108 * Note: the following optional parameters can be set any time
109 * before EVP_MAC_final().
112 *p++ = OSSL_PARAM_construct_int(OSSL_MAC_PARAM_XOF, &xof_enabled);
113 *p++ = OSSL_PARAM_construct_int(OSSL_MAC_PARAM_SIZE, &out_len);
114 *p = OSSL_PARAM_construct_end();
115 if (!EVP_MAC_CTX_set_params(ctx, params))
118 /* The update may be called multiple times here for streamed input */
119 if (!EVP_MAC_update(ctx, in, in_len))
121 if (!EVP_MAC_final(ctx, out, &l, out_len))
125 EVP_MAC_CTX_free(ctx);
131 L<EVP_MAC_CTX_get_params(3)>, L<EVP_MAC_CTX_set_params(3)>,
132 L<EVP_MAC(3)/PARAMETERS>, L<OSSL_PARAM(3)>
136 Copyright 2018-2021 The OpenSSL Project Authors. All Rights Reserved.
138 Licensed under the Apache License 2.0 (the "License"). You may not use
139 this file except in compliance with the License. You can obtain a copy
140 in the file LICENSE in the source distribution or at
141 L<https://www.openssl.org/source/license.html>.