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