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 (except for "block-size") can be set with
31 EVP_MAC_CTX_set_params().
32 Furthermore, the "size" parameter can be retrieved with
33 EVP_MAC_CTX_get_params(), or with EVP_MAC_CTX_get_mac_size().
34 The length of the "size" parameter should not exceed that of a B<size_t>.
35 Likewise, the "block-size" parameter can be retrieved with
36 EVP_MAC_CTX_get_params(), or with EVP_MAC_CTX_get_block_size().
41 =item "key" (B<OSSL_MAC_PARAM_KEY>) <octet string>
44 Setting this parameter is identical to passing a I<key> to L<EVP_MAC_init(3)>.
45 The length of the key (in bytes) must be in the range 4...512.
47 =item "custom" (B<OSSL_MAC_PARAM_CUSTOM>) <octet string>
49 Sets the customization string.
50 It is an optional value with a length of at most 512 bytes, and is
53 =item "size" (B<OSSL_MAC_PARAM_SIZE>) <unsigned integer>
56 By default, it is 32 for C<KMAC-128> and 64 for C<KMAC-256>.
58 =item "block-size" (B<OSSL_MAC_PARAM_BLOCK_SIZE>) <unsigned integer>
60 Gets the MAC block size.
61 It is 168 for C<KMAC-128> and 136 for C<KMAC-256>.
63 =item "xof" (B<OSSL_MAC_PARAM_XOF>) <integer>
65 The "xof" parameter value is expected to be 1 or 0. Use 1 to enable XOF mode.
66 The default value is 0.
70 The "custom" parameter must be set as part of or before the EVP_MAC_init() call.
71 The "xof" and "size" parameters can be set at any time before EVP_MAC_final().
72 The "key" parameter is set as part of the EVP_MAC_init() call, but can be
73 set before it instead.
77 #include <openssl/evp.h>
78 #include <openssl/params.h>
80 static int do_kmac(const unsigned char *in, size_t in_len,
81 const unsigned char *key, size_t key_len,
82 const unsigned char *custom, size_t custom_len,
83 int xof_enabled, unsigned char *out, int out_len)
85 EVP_MAC_CTX *ctx = NULL;
87 OSSL_PARAM params[4], *p;
91 mac = EVP_MAC_fetch(NULL, "KMAC-128", NULL);
94 ctx = EVP_MAC_CTX_new(mac);
95 /* The mac can be freed after it is used by EVP_MAC_CTX_new */
101 * Setup parameters required before calling EVP_MAC_init()
102 * The parameters OSSL_MAC_PARAM_XOF and OSSL_MAC_PARAM_SIZE may also be
103 * used at this point.
106 *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
107 (void *)key, key_len);
108 if (custom != NULL && custom_len != 0)
109 *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_CUSTOM,
110 (void *)custom, custom_len);
111 *p = OSSL_PARAM_construct_end();
112 if (!EVP_MAC_CTX_set_params(ctx, params))
115 if (!EVP_MAC_init(ctx))
119 * Note: the following optional parameters can be set any time
120 * before EVP_MAC_final().
123 *p++ = OSSL_PARAM_construct_int(OSSL_MAC_PARAM_XOF, &xof_enabled);
124 *p++ = OSSL_PARAM_construct_int(OSSL_MAC_PARAM_SIZE, &out_len);
125 *p = OSSL_PARAM_construct_end();
126 if (!EVP_MAC_CTX_set_params(ctx, params))
129 /* The update may be called multiple times here for streamed input */
130 if (!EVP_MAC_update(ctx, in, in_len))
132 if (!EVP_MAC_final(ctx, out, &l, out_len))
136 EVP_MAC_CTX_free(ctx);
142 L<EVP_MAC_CTX_get_params(3)>, L<EVP_MAC_CTX_set_params(3)>,
143 L<EVP_MAC(3)/PARAMETERS>, L<OSSL_PARAM(3)>
147 Copyright 2018-2021 The OpenSSL Project Authors. All Rights Reserved.
149 Licensed under the Apache License 2.0 (the "License"). You may not use
150 this file except in compliance with the License. You can obtain a copy
151 in the file LICENSE in the source distribution or at
152 L<https://www.openssl.org/source/license.html>.