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