1 /*
2 * Copyright 2021 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/obj_mac.h>
15 #include <openssl/params.h>
16
17 /*
18 * test vector from
19 * https://datatracker.ietf.org/doc/html/rfc7914
20 */
21
22 /*
23 * Hard coding a password into an application is very bad.
24 * It is done here solely for educational purposes.
25 */
26 static unsigned char password[] = {
27 'p', 'a', 's', 's', 'w', 'o', 'r', 'd'
28 };
29
30 /*
31 * The salt is better not being hard coded too. Each password should have a
32 * different salt if possible. The salt is not considered secret information
33 * and is safe to store with an encrypted password.
34 */
35 static unsigned char scrypt_salt[] = {
36 'N', 'a', 'C', 'l'
37 };
38
39 /*
40 * The SCRYPT parameters can be variable or hard coded. The disadvantage with
41 * hard coding them is that they cannot easily be adjusted for future
42 * technological improvements appear.
43 */
44 static unsigned int scrypt_n = 1024;
45 static unsigned int scrypt_r = 8;
46 static unsigned int scrypt_p = 16;
47
48 static const unsigned char expected_output[] = {
49
50 0xfd, 0xba, 0xbe, 0x1c, 0x9d, 0x34, 0x72, 0x00,
51 0x78, 0x56, 0xe7, 0x19, 0x0d, 0x01, 0xe9, 0xfe,
52 0x7c, 0x6a, 0xd7, 0xcb, 0xc8, 0x23, 0x78, 0x30,
53 0xe7, 0x73, 0x76, 0x63, 0x4b, 0x37, 0x31, 0x62,
54 0x2e, 0xaf, 0x30, 0xd9, 0x2e, 0x22, 0xa3, 0x88,
55 0x6f, 0xf1, 0x09, 0x27, 0x9d, 0x98, 0x30, 0xda,
56 0xc7, 0x27, 0xaf, 0xb9, 0x4a, 0x83, 0xee, 0x6d,
57 0x83, 0x60, 0xcb, 0xdf, 0xa2, 0xcc, 0x06, 0x40
58 };
59
main(int argc,char ** argv)60 int main(int argc, char **argv)
61 {
62 int rv = 1;
63 EVP_KDF *kdf = NULL;
64 EVP_KDF_CTX *kctx = NULL;
65 unsigned char out[64];
66 OSSL_PARAM params[6], *p = params;
67 OSSL_LIB_CTX *library_context = NULL;
68
69 library_context = OSSL_LIB_CTX_new();
70 if (library_context == NULL) {
71 fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
72 goto end;
73 }
74
75 /* Fetch the key derivation function implementation */
76 kdf = EVP_KDF_fetch(library_context, "SCRYPT", NULL);
77 if (kdf == NULL) {
78 fprintf(stderr, "EVP_KDF_fetch() returned NULL\n");
79 goto end;
80 }
81
82 /* Create a context for the key derivation operation */
83 kctx = EVP_KDF_CTX_new(kdf);
84 if (kctx == NULL) {
85 fprintf(stderr, "EVP_KDF_CTX_new() returned NULL\n");
86 goto end;
87 }
88
89 /* Set password */
90 *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_PASSWORD, password,
91 sizeof(password));
92 /* Set salt */
93 *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT, scrypt_salt,
94 sizeof(scrypt_salt));
95 /* Set N (default 1048576) */
96 *p++ = OSSL_PARAM_construct_uint(OSSL_KDF_PARAM_SCRYPT_N, &scrypt_n);
97 /* Set R (default 8) */
98 *p++ = OSSL_PARAM_construct_uint(OSSL_KDF_PARAM_SCRYPT_R, &scrypt_r);
99 /* Set P (default 1) */
100 *p++ = OSSL_PARAM_construct_uint(OSSL_KDF_PARAM_SCRYPT_P, &scrypt_p);
101 *p = OSSL_PARAM_construct_end();
102
103 /* Derive the key */
104 if (EVP_KDF_derive(kctx, out, sizeof(out), params) != 1) {
105 fprintf(stderr, "EVP_KDF_derive() failed\n");
106 goto end;
107 }
108
109 if (CRYPTO_memcmp(expected_output, out, sizeof(expected_output)) != 0) {
110 fprintf(stderr, "Generated key does not match expected value\n");
111 goto end;
112 }
113
114 rv = 0;
115 end:
116 EVP_KDF_CTX_free(kctx);
117 EVP_KDF_free(kdf);
118 OSSL_LIB_CTX_free(library_context);
119 return rv;
120 }
121