1 /*-
2 * Copyright 2019-2024 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 /*-
11 * Example of using EVP_MD_fetch and EVP_Digest* methods to calculate
12 * a digest of static buffers
13 * You can find SHA3 test vectors from NIST here:
14 * https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Algorithm-Validation-Program/documents/sha3/sha-3bytetestvectors.zip
15 * For example, contains these lines:
16 Len = 80
17 Msg = 1ca984dcc913344370cf
18 MD = 6915ea0eeffb99b9b246a0e34daf3947852684c3d618260119a22835659e4f23d4eb66a15d0affb8e93771578f5e8f25b7a5f2a55f511fb8b96325ba2cd14816
19 * use xxd convert the hex message string to binary input for BIO_f_md:
20 * echo "1ca984dcc913344370cf" | xxd -r -p | ./BIO_f_md
21 * and then verify the output matches MD above.
22 */
23
24 #include <string.h>
25 #include <stdio.h>
26 #include <openssl/err.h>
27 #include <openssl/bio.h>
28 #include <openssl/evp.h>
29
30 #ifdef OPENSSL_SYS_WINDOWS
31 # define fileno _fileno
32 #endif
33
34 /*-
35 * This demonstration will show how to digest data using
36 * a BIO configured with a message digest
37 * A message digest name may be passed as an argument.
38 * The default digest is SHA3-512
39 */
40
main(int argc,char * argv[])41 int main(int argc, char *argv[])
42 {
43 int ret = EXIT_FAILURE;
44 OSSL_LIB_CTX *library_context = NULL;
45 BIO *input = NULL;
46 BIO *bio_digest = NULL, *reading = NULL;
47 EVP_MD *md = NULL;
48 unsigned char buffer[512];
49 int digest_size;
50 char *digest_value = NULL;
51 int j;
52
53 input = BIO_new_fd(fileno(stdin), 1);
54 if (input == NULL) {
55 fprintf(stderr, "BIO_new_fd() for stdin returned NULL\n");
56 goto cleanup;
57 }
58 library_context = OSSL_LIB_CTX_new();
59 if (library_context == NULL) {
60 fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
61 goto cleanup;
62 }
63
64 /*
65 * Fetch a message digest by name
66 * The algorithm name is case insensitive.
67 * See providers(7) for details about algorithm fetching
68 */
69 md = EVP_MD_fetch(library_context, "SHA3-512", NULL);
70 if (md == NULL) {
71 fprintf(stderr, "EVP_MD_fetch did not find SHA3-512.\n");
72 goto cleanup;
73 }
74 digest_size = EVP_MD_get_size(md);
75 if (digest_size <= 0) {
76 fprintf(stderr, "EVP_MD_get_size returned invalid size.\n");
77 goto cleanup;
78 }
79
80 digest_value = OPENSSL_malloc(digest_size);
81 if (digest_value == NULL) {
82 fprintf(stderr, "Can't allocate %lu bytes for the digest value.\n", (unsigned long)digest_size);
83 goto cleanup;
84 }
85 /* Make a bio that uses the digest */
86 bio_digest = BIO_new(BIO_f_md());
87 if (bio_digest == NULL) {
88 fprintf(stderr, "BIO_new(BIO_f_md()) returned NULL\n");
89 goto cleanup;
90 }
91 /* set our bio_digest BIO to digest data */
92 if (BIO_set_md(bio_digest, md) != 1) {
93 fprintf(stderr, "BIO_set_md failed.\n");
94 goto cleanup;
95 }
96 /*-
97 * We will use BIO chaining so that as we read, the digest gets updated
98 * See the man page for BIO_push
99 */
100 reading = BIO_push(bio_digest, input);
101
102 while (BIO_read(reading, buffer, sizeof(buffer)) > 0)
103 ;
104
105 /*-
106 * BIO_gets must be used to calculate the final
107 * digest value and then copy it to digest_value.
108 */
109 if (BIO_gets(bio_digest, digest_value, digest_size) != digest_size) {
110 fprintf(stderr, "BIO_gets(bio_digest) failed\n");
111 goto cleanup;
112 }
113 for (j = 0; j < digest_size; j++) {
114 fprintf(stdout, "%02x", (unsigned char)digest_value[j]);
115 }
116 fprintf(stdout, "\n");
117 ret = EXIT_SUCCESS;
118
119 cleanup:
120 if (ret != EXIT_SUCCESS)
121 ERR_print_errors_fp(stderr);
122
123 OPENSSL_free(digest_value);
124 BIO_free(input);
125 BIO_free(bio_digest);
126 EVP_MD_free(md);
127 OSSL_LIB_CTX_free(library_context);
128
129 return ret;
130 }
131