demos/digest/EVP_MD_demo.c

   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 /*
  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
  79 int demonstrate_digest(void)
  80 {
  81     OSSL_LIB_CTX *library_context;
  82     int ret = 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         ret = 1;
 165     }
 166
 167 cleanup:
 168     if (ret != 1)
 169         ERR_print_errors_fp(stderr);
 170     /* OpenSSL free functions will ignore NULL arguments */
 171     EVP_MD_CTX_free(digest_context);
 172     OPENSSL_free(digest_value);
 173     EVP_MD_free(message_digest);
 174
 175     OSSL_LIB_CTX_free(library_context);
 176     return ret;
 177 }
 178
 179 int main(void)
 180 {
 181     return demonstrate_digest() ? EXIT_SUCCESS : EXIT_FAILURE;
 182 }