xref: /openssl/demos/kdf/pbkdf2.c (revision 86db9588)
1 /*
2  * Copyright 2021-2023 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/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 pbkdf2_salt[] = {
36     'N', 'a', 'C', 'l'
37 };
38 
39 /*
40  * The iteration parameter 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 pbkdf2_iterations = 80000;
45 
46 static const unsigned char expected_output[] = {
47 
48     0x4d, 0xdc, 0xd8, 0xf6, 0x0b, 0x98, 0xbe, 0x21,
49     0x83, 0x0c, 0xee, 0x5e, 0xf2, 0x27, 0x01, 0xf9,
50     0x64, 0x1a, 0x44, 0x18, 0xd0, 0x4c, 0x04, 0x14,
51     0xae, 0xff, 0x08, 0x87, 0x6b, 0x34, 0xab, 0x56,
52     0xa1, 0xd4, 0x25, 0xa1, 0x22, 0x58, 0x33, 0x54,
53     0x9a, 0xdb, 0x84, 0x1b, 0x51, 0xc9, 0xb3, 0x17,
54     0x6a, 0x27, 0x2b, 0xde, 0xbb, 0xa1, 0xd0, 0x78,
55     0x47, 0x8f, 0x62, 0xb3, 0x97, 0xf3, 0x3c, 0x8d
56 };
57 
main(int argc,char ** argv)58 int main(int argc, char **argv)
59 {
60     int ret = EXIT_FAILURE;
61     EVP_KDF *kdf = NULL;
62     EVP_KDF_CTX *kctx = NULL;
63     unsigned char out[64];
64     OSSL_PARAM params[5], *p = params;
65     OSSL_LIB_CTX *library_context = NULL;
66 
67     library_context = OSSL_LIB_CTX_new();
68     if (library_context == NULL) {
69         fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
70         goto end;
71     }
72 
73     /* Fetch the key derivation function implementation */
74     kdf = EVP_KDF_fetch(library_context, "PBKDF2", NULL);
75     if (kdf == NULL) {
76         fprintf(stderr, "EVP_KDF_fetch() returned NULL\n");
77         goto end;
78     }
79 
80     /* Create a context for the key derivation operation */
81     kctx = EVP_KDF_CTX_new(kdf);
82     if (kctx == NULL) {
83         fprintf(stderr, "EVP_KDF_CTX_new() returned NULL\n");
84         goto end;
85     }
86 
87     /* Set password */
88     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_PASSWORD, password,
89                                              sizeof(password));
90     /* Set salt */
91     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT, pbkdf2_salt,
92                                              sizeof(pbkdf2_salt));
93     /* Set iteration count (default 2048) */
94     *p++ = OSSL_PARAM_construct_uint(OSSL_KDF_PARAM_ITER, &pbkdf2_iterations);
95     /* Set the underlying hash function used to derive the key */
96     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
97                                             "SHA256", 0);
98     *p = OSSL_PARAM_construct_end();
99 
100     /* Derive the key */
101     if (EVP_KDF_derive(kctx, out, sizeof(out), params) != 1) {
102         fprintf(stderr, "EVP_KDF_derive() failed\n");
103         goto end;
104     }
105 
106     if (CRYPTO_memcmp(expected_output, out, sizeof(expected_output)) != 0) {
107         fprintf(stderr, "Generated key does not match expected value\n");
108         goto end;
109     }
110 
111     printf("Success\n");
112 
113     ret = EXIT_SUCCESS;
114 end:
115     EVP_KDF_CTX_free(kctx);
116     EVP_KDF_free(kdf);
117     OSSL_LIB_CTX_free(library_context);
118     return ret;
119 }
120