1 /*
2 * Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <stdio.h>
11 #include <openssl/core_names.h>
12 #include <openssl/crypto.h>
13 #include <openssl/kdf.h>
14 #include <openssl/params.h>
15 #include <openssl/thread.h>
16
17 /*
18 * Example showing how to use Argon2 KDF.
19 * See man EVP_KDF-ARGON2 for more information.
20 *
21 * test vector from
22 * https://datatracker.ietf.org/doc/html/rfc9106
23 */
24
25 /*
26 * Hard coding a password into an application is very bad.
27 * It is done here solely for educational purposes.
28 */
29 static unsigned char password[] = {
30 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
31 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
32 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
33 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01
34 };
35
36 /*
37 * The salt is better not being hard coded too. Each password should have a
38 * different salt if possible. The salt is not considered secret information
39 * and is safe to store with an encrypted password.
40 */
41 static unsigned char salt[] = {
42 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
43 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02
44 };
45
46 /*
47 * Optional secret for KDF
48 */
49 static unsigned char secret[] = {
50 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03
51 };
52
53 /*
54 * Optional additional data
55 */
56 static unsigned char ad[] = {
57 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
58 0x04, 0x04, 0x04, 0x04
59 };
60
61 /*
62 * Argon2 cost parameters
63 */
64 static uint32_t memory_cost = 32;
65 static uint32_t iteration_cost = 3;
66 static uint32_t parallel_cost = 4;
67
68 static const unsigned char expected_output[] = {
69 0x0d, 0x64, 0x0d, 0xf5, 0x8d, 0x78, 0x76, 0x6c,
70 0x08, 0xc0, 0x37, 0xa3, 0x4a, 0x8b, 0x53, 0xc9,
71 0xd0, 0x1e, 0xf0, 0x45, 0x2d, 0x75, 0xb6, 0x5e,
72 0xb5, 0x25, 0x20, 0xe9, 0x6b, 0x01, 0xe6, 0x59
73 };
74
main(int argc,char ** argv)75 int main(int argc, char **argv)
76 {
77 int rv = EXIT_FAILURE;
78 EVP_KDF *kdf = NULL;
79 EVP_KDF_CTX *kctx = NULL;
80 unsigned char out[32];
81 OSSL_PARAM params[9], *p = params;
82 OSSL_LIB_CTX *library_context = NULL;
83 unsigned int threads;
84
85 library_context = OSSL_LIB_CTX_new();
86 if (library_context == NULL) {
87 fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
88 goto end;
89 }
90
91 /* Fetch the key derivation function implementation */
92 kdf = EVP_KDF_fetch(library_context, "argon2id", NULL);
93 if (kdf == NULL) {
94 fprintf(stderr, "EVP_KDF_fetch() returned NULL\n");
95 goto end;
96 }
97
98 /* Create a context for the key derivation operation */
99 kctx = EVP_KDF_CTX_new(kdf);
100 if (kctx == NULL) {
101 fprintf(stderr, "EVP_KDF_CTX_new() returned NULL\n");
102 goto end;
103 }
104
105 /*
106 * Thread support can be turned off; use serialization if we cannot
107 * set requested number of threads.
108 */
109 threads = parallel_cost;
110 if (OSSL_set_max_threads(library_context, parallel_cost) != 1) {
111 uint64_t max_threads = OSSL_get_max_threads(library_context);
112
113 if (max_threads == 0)
114 threads = 1;
115 else if (max_threads < parallel_cost)
116 threads = max_threads;
117 }
118
119 /* Set password */
120 *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_PASSWORD, password, sizeof(password));
121 /* Set salt */
122 *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT, salt, sizeof(salt));
123 /* Set optional additional data */
124 *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_ARGON2_AD, ad, sizeof(ad));
125 /* Set optional secret */
126 *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SECRET, secret, sizeof(secret));
127 /* Set iteration count */
128 *p++ = OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_ITER, &iteration_cost);
129 /* Set threads performing derivation (can be decreased) */
130 *p++ = OSSL_PARAM_construct_uint(OSSL_KDF_PARAM_THREADS, &threads);
131 /* Set parallel cost */
132 *p++ = OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_ARGON2_LANES, ¶llel_cost);
133 /* Set memory requirement */
134 *p++ = OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_ARGON2_MEMCOST, &memory_cost);
135 *p = OSSL_PARAM_construct_end();
136
137 /* Derive the key */
138 if (EVP_KDF_derive(kctx, out, sizeof(out), params) != 1) {
139 fprintf(stderr, "EVP_KDF_derive() failed\n");
140 goto end;
141 }
142
143 if (CRYPTO_memcmp(expected_output, out, sizeof(expected_output)) != 0) {
144 fprintf(stderr, "Generated key does not match expected value\n");
145 goto end;
146 }
147
148 printf("Success\n");
149
150 rv = EXIT_SUCCESS;
151 end:
152 EVP_KDF_CTX_free(kctx);
153 EVP_KDF_free(kdf);
154 OSSL_LIB_CTX_free(library_context);
155 return rv;
156 }
157
