1 /*-
2 * Copyright 2019-2021 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 /*-
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 EVP_MD_stdin:
20 * echo "1ca984dcc913344370cf" | xxd -r -p | ./EVP_MD_stdin
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/evp.h>
28
29 /*-
30 * This demonstration will show how to digest data using
31 * a BIO created to read from stdin
32 */
33
demonstrate_digest(BIO * input)34 int demonstrate_digest(BIO *input)
35 {
36 OSSL_LIB_CTX *library_context = NULL;
37 int result = 0;
38 const char * option_properties = NULL;
39 EVP_MD *message_digest = NULL;
40 EVP_MD_CTX *digest_context = NULL;
41 unsigned int digest_length;
42 unsigned char *digest_value = NULL;
43 unsigned char buffer[512];
44 int ii;
45
46 library_context = OSSL_LIB_CTX_new();
47 if (library_context == NULL) {
48 fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
49 goto cleanup;
50 }
51
52 /*
53 * Fetch a message digest by name
54 * The algorithm name is case insensitive.
55 * See providers(7) for details about algorithm fetching
56 */
57 message_digest = EVP_MD_fetch(library_context,
58 "SHA3-512", option_properties);
59 if (message_digest == NULL) {
60 fprintf(stderr, "EVP_MD_fetch could not find SHA3-512.");
61 ERR_print_errors_fp(stderr);
62 OSSL_LIB_CTX_free(library_context);
63 return 0;
64 }
65 /* Determine the length of the fetched digest type */
66 digest_length = EVP_MD_get_size(message_digest);
67 if (digest_length <= 0) {
68 fprintf(stderr, "EVP_MD_get_size returned invalid size.\n");
69 goto cleanup;
70 }
71
72 digest_value = OPENSSL_malloc(digest_length);
73 if (digest_value == NULL) {
74 fprintf(stderr, "No memory.\n");
75 goto cleanup;
76 }
77 /*
78 * Make a message digest context to hold temporary state
79 * during digest creation
80 */
81 digest_context = EVP_MD_CTX_new();
82 if (digest_context == NULL) {
83 fprintf(stderr, "EVP_MD_CTX_new failed.\n");
84 ERR_print_errors_fp(stderr);
85 goto cleanup;
86 }
87 /*
88 * Initialize the message digest context to use the fetched
89 * digest provider
90 */
91 if (EVP_DigestInit(digest_context, message_digest) != 1) {
92 fprintf(stderr, "EVP_DigestInit failed.\n");
93 ERR_print_errors_fp(stderr);
94 goto cleanup;
95 }
96 while ((ii = BIO_read(input, buffer, sizeof(buffer))) > 0) {
97 if (EVP_DigestUpdate(digest_context, buffer, ii) != 1) {
98 fprintf(stderr, "EVP_DigestUpdate() failed.\n");
99 goto cleanup;
100 }
101 }
102 if (EVP_DigestFinal(digest_context, digest_value, &digest_length) != 1) {
103 fprintf(stderr, "EVP_DigestFinal() failed.\n");
104 goto cleanup;
105 }
106 result = 1;
107 for (ii=0; ii<digest_length; ii++) {
108 fprintf(stdout, "%02x", digest_value[ii]);
109 }
110 fprintf(stdout, "\n");
111
112 cleanup:
113 if (result != 1)
114 ERR_print_errors_fp(stderr);
115 /* OpenSSL free functions will ignore NULL arguments */
116 EVP_MD_CTX_free(digest_context);
117 OPENSSL_free(digest_value);
118 EVP_MD_free(message_digest);
119
120 OSSL_LIB_CTX_free(library_context);
121 return result;
122 }
123
main(void)124 int main(void)
125 {
126 int result = 1;
127 BIO *input = BIO_new_fd(fileno(stdin), 1);
128
129 if (input != NULL) {
130 result = demonstrate_digest(input);
131 BIO_free(input);
132 }
133 return result;
134 }
135
