Home | History | Annotate | Line # | Download | only in digest 
      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 /*-
     31  * This demonstration will show how to digest data using
     32  * a BIO configured with a message digest
     33  * A message digest name may be passed as an argument.
     34  * The default digest is SHA3-512
     35  */
     36 
     37 int main(int argc, char *argv[])
     38 {
     39     int ret = EXIT_FAILURE;
     40     OSSL_LIB_CTX *library_context = NULL;
     41     BIO *input = NULL;
     42     BIO *bio_digest = NULL, *reading = NULL;
     43     EVP_MD *md = NULL;
     44     unsigned char buffer[512];
     45     int digest_size;
     46     char *digest_value = NULL;
     47     int j;
     48 
     49     input = BIO_new_fd(fileno(stdin), 1);
     50     if (input == NULL) {
     51         fprintf(stderr, "BIO_new_fd() for stdin returned NULL\n");
     52         goto cleanup;
     53     }
     54     library_context = OSSL_LIB_CTX_new();
     55     if (library_context == NULL) {
     56         fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
     57         goto cleanup;
     58     }
     59 
     60     /*
     61      * Fetch a message digest by name
     62      * The algorithm name is case insensitive.
     63      * See providers(7) for details about algorithm fetching
     64      */
     65     md = EVP_MD_fetch(library_context, "SHA3-512", NULL);
     66     if (md == NULL) {
     67         fprintf(stderr, "EVP_MD_fetch did not find SHA3-512.\n");
     68         goto cleanup;
     69     }
     70     digest_size = EVP_MD_get_size(md);
     71     if (digest_size <= 0) {
     72         fprintf(stderr, "EVP_MD_get_size returned invalid size.\n");
     73         goto cleanup;
     74     }
     75 
     76     digest_value = OPENSSL_malloc(digest_size);
     77     if (digest_value == NULL) {
     78         fprintf(stderr, "Can't allocate %lu bytes for the digest value.\n", (unsigned long)digest_size);
     79         goto cleanup;
     80     }
     81     /* Make a bio that uses the digest */
     82     bio_digest = BIO_new(BIO_f_md());
     83     if (bio_digest == NULL) {
     84         fprintf(stderr, "BIO_new(BIO_f_md()) returned NULL\n");
     85         goto cleanup;
     86     }
     87     /* set our bio_digest BIO to digest data */
     88     if (BIO_set_md(bio_digest, md) != 1) {
     89         fprintf(stderr, "BIO_set_md failed.\n");
     90         goto cleanup;
     91     }
     92     /*-
     93      * We will use BIO chaining so that as we read, the digest gets updated
     94      * See the man page for BIO_push
     95      */
     96     reading = BIO_push(bio_digest, input);
     97 
     98     while (BIO_read(reading, buffer, sizeof(buffer)) > 0)
     99         ;
    100 
    101     /*-
    102      * BIO_gets must be used to calculate the final
    103      * digest value and then copy it to digest_value.
    104      */
    105     if (BIO_gets(bio_digest, digest_value, digest_size) != digest_size) {
    106         fprintf(stderr, "BIO_gets(bio_digest) failed\n");
    107         goto cleanup;
    108     }
    109     for (j = 0; j < digest_size; j++) {
    110         fprintf(stdout, "%02x", (unsigned char)digest_value[j]);
    111     }
    112     fprintf(stdout, "\n");
    113     ret = EXIT_SUCCESS;
    114 
    115 cleanup:
    116     if (ret != EXIT_SUCCESS)
    117         ERR_print_errors_fp(stderr);
    118 
    119     OPENSSL_free(digest_value);
    120     BIO_free(input);
    121     BIO_free(bio_digest);
    122     EVP_MD_free(md);
    123     OSSL_LIB_CTX_free(library_context);
    124 
    125     return ret;
    126 }
    127