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 /*
11 * Example of using EVP_MD_fetch and EVP_Digest* methods to calculate
12 * a digest of static buffers
13 */
14
15 #include <string.h>
16 #include <stdio.h>
17 #include <openssl/err.h>
18 #include <openssl/evp.h>
19
20 /*-
21 * This demonstration will show how to digest data using
22 * the soliloqy from Hamlet scene 1 act 3
23 * The soliloqy is split into two parts to demonstrate using EVP_DigestUpdate
24 * more than once.
25 */
26
27 const char * hamlet_1 =
28 "To be, or not to be, that is the question,\n"
29 "Whether tis nobler in the minde to suffer\n"
30 "The ſlings and arrowes of outragious fortune,\n"
31 "Or to take Armes again in a sea of troubles,\n"
32 "And by opposing, end them, to die to sleep;\n"
33 "No more, and by a sleep, to say we end\n"
34 "The heart-ache, and the thousand natural shocks\n"
35 "That flesh is heir to? tis a consumation\n"
36 "Devoutly to be wished. To die to sleep,\n"
37 "To sleepe, perchance to dreame, Aye, there's the rub,\n"
38 "For in that sleep of death what dreams may come\n"
39 "When we haue shuffled off this mortal coil\n"
40 "Must give us pause. There's the respect\n"
41 "That makes calamity of so long life:\n"
42 "For who would bear the Ships and Scorns of time,\n"
43 "The oppressor's wrong, the proud man's Contumely,\n"
44 "The pangs of dispised love, the Law's delay,\n"
45 ;
46 const char * hamlet_2 =
47 "The insolence of Office, and the spurns\n"
48 "That patient merit of the'unworthy takes,\n"
49 "When he himself might his Quietas make\n"
50 "With a bare bodkin? Who would fardels bear,\n"
51 "To grunt and sweat under a weary life,\n"
52 "But that the dread of something after death,\n"
53 "The undiscovered country, from whose bourn\n"
54 "No traveller returns, puzzles the will,\n"
55 "And makes us rather bear those ills we have,\n"
56 "Then fly to others we know not of?\n"
57 "Thus conscience does make cowards of us all,\n"
58 "And thus the native hue of Resolution\n"
59 "Is sickled o'er with the pale cast of Thought,\n"
60 "And enterprises of great pith and moment,\n"
61 "With this regard their currents turn awry,\n"
62 "And lose the name of Action. Soft you now,\n"
63 "The fair Ophelia? Nymph in thy Orisons\n"
64 "Be all my sins remember'd.\n"
65 ;
66
67 /* The known value of the SHA3-512 digest of the above soliloqy */
68 const unsigned char known_answer[] = {
69 0xbb, 0x69, 0xf8, 0x09, 0x9c, 0x2e, 0x00, 0x3d,
70 0xa4, 0x29, 0x5f, 0x59, 0x4b, 0x89, 0xe4, 0xd9,
71 0xdb, 0xa2, 0xe5, 0xaf, 0xa5, 0x87, 0x73, 0x9d,
72 0x83, 0x72, 0xcf, 0xea, 0x84, 0x66, 0xc1, 0xf9,
73 0xc9, 0x78, 0xef, 0xba, 0x3d, 0xe9, 0xc1, 0xff,
74 0xa3, 0x75, 0xc7, 0x58, 0x74, 0x8e, 0x9c, 0x1d,
75 0x14, 0xd9, 0xdd, 0xd1, 0xfd, 0x24, 0x30, 0xd6,
76 0x81, 0xca, 0x8f, 0x78, 0x29, 0x19, 0x9a, 0xfe,
77 };
78
demonstrate_digest(void)79 int demonstrate_digest(void)
80 {
81 OSSL_LIB_CTX *library_context;
82 int result = 0;
83 const char *option_properties = NULL;
84 EVP_MD *message_digest = NULL;
85 EVP_MD_CTX *digest_context = NULL;
86 unsigned int digest_length;
87 unsigned char *digest_value = NULL;
88 int j;
89
90 library_context = OSSL_LIB_CTX_new();
91 if (library_context == NULL) {
92 fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
93 goto cleanup;
94 }
95
96 /*
97 * Fetch a message digest by name
98 * The algorithm name is case insensitive.
99 * See providers(7) for details about algorithm fetching
100 */
101 message_digest = EVP_MD_fetch(library_context,
102 "SHA3-512", option_properties);
103 if (message_digest == NULL) {
104 fprintf(stderr, "EVP_MD_fetch could not find SHA3-512.");
105 goto cleanup;
106 }
107 /* Determine the length of the fetched digest type */
108 digest_length = EVP_MD_get_size(message_digest);
109 if (digest_length <= 0) {
110 fprintf(stderr, "EVP_MD_get_size returned invalid size.\n");
111 goto cleanup;
112 }
113
114 digest_value = OPENSSL_malloc(digest_length);
115 if (digest_value == NULL) {
116 fprintf(stderr, "No memory.\n");
117 goto cleanup;
118 }
119 /*
120 * Make a message digest context to hold temporary state
121 * during digest creation
122 */
123 digest_context = EVP_MD_CTX_new();
124 if (digest_context == NULL) {
125 fprintf(stderr, "EVP_MD_CTX_new failed.\n");
126 goto cleanup;
127 }
128 /*
129 * Initialize the message digest context to use the fetched
130 * digest provider
131 */
132 if (EVP_DigestInit(digest_context, message_digest) != 1) {
133 fprintf(stderr, "EVP_DigestInit failed.\n");
134 goto cleanup;
135 }
136 /* Digest parts one and two of the soliloqy */
137 if (EVP_DigestUpdate(digest_context, hamlet_1, strlen(hamlet_1)) != 1) {
138 fprintf(stderr, "EVP_DigestUpdate(hamlet_1) failed.\n");
139 goto cleanup;
140 }
141 if (EVP_DigestUpdate(digest_context, hamlet_2, strlen(hamlet_2)) != 1) {
142 fprintf(stderr, "EVP_DigestUpdate(hamlet_2) failed.\n");
143 goto cleanup;
144 }
145 if (EVP_DigestFinal(digest_context, digest_value, &digest_length) != 1) {
146 fprintf(stderr, "EVP_DigestFinal() failed.\n");
147 goto cleanup;
148 }
149 for (j=0; j<digest_length; j++) {
150 fprintf(stdout, "%02x", digest_value[j]);
151 }
152 fprintf(stdout, "\n");
153 /* Check digest_value against the known answer */
154 if ((size_t)digest_length != sizeof(known_answer)) {
155 fprintf(stdout, "Digest length(%d) not equal to known answer length(%lu).\n",
156 digest_length, sizeof(known_answer));
157 } else if (memcmp(digest_value, known_answer, digest_length) != 0) {
158 for (j=0; j<sizeof(known_answer); j++) {
159 fprintf(stdout, "%02x", known_answer[j] );
160 }
161 fprintf(stdout, "\nDigest does not match known answer\n");
162 } else {
163 fprintf(stdout, "Digest computed properly.\n");
164 result = 1;
165 }
166
167
168 cleanup:
169 if (result != 1)
170 ERR_print_errors_fp(stderr);
171 /* OpenSSL free functions will ignore NULL arguments */
172 EVP_MD_CTX_free(digest_context);
173 OPENSSL_free(digest_value);
174 EVP_MD_free(message_digest);
175
176 OSSL_LIB_CTX_free(library_context);
177 return result;
178 }
179
main(void)180 int main(void)
181 {
182 return demonstrate_digest() == 0;
183 }
184