1 /*- 2 * Copyright 2022 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_MAC_ methods to calculate 12 * a HMAC of static buffers 13 */ 14 15 #include <string.h> 16 #include <stdio.h> 17 #include <openssl/crypto.h> 18 #include <openssl/core_names.h> 19 #include <openssl/err.h> 20 #include <openssl/evp.h> 21 #include <openssl/hmac.h> 22 #include <openssl/params.h> 23 24 /* 25 * Hard coding the key into an application is very bad. 26 * It is done here solely for educational purposes. 27 */ 28 static unsigned char key[] = { 29 0x25, 0xfd, 0x12, 0x99, 0xdf, 0xad, 0x1a, 0x03, 30 0x0a, 0x81, 0x3c, 0x2d, 0xcc, 0x05, 0xd1, 0x5c, 31 0x17, 0x7a, 0x36, 0x73, 0x17, 0xef, 0x41, 0x75, 32 0x71, 0x18, 0xe0, 0x1a, 0xda, 0x99, 0xc3, 0x61, 33 0x38, 0xb5, 0xb1, 0xe0, 0x82, 0x2c, 0x70, 0xa4, 34 0xc0, 0x8e, 0x5e, 0xf9, 0x93, 0x9f, 0xcf, 0xf7, 35 0x32, 0x4d, 0x0c, 0xbd, 0x31, 0x12, 0x0f, 0x9a, 36 0x15, 0xee, 0x82, 0xdb, 0x8d, 0x29, 0x54, 0x14, 37 }; 38 39 static const unsigned char data[] = 40 "To be, or not to be, that is the question,\n" 41 "Whether tis nobler in the minde to suffer\n" 42 "The ſlings and arrowes of outragious fortune,\n" 43 "Or to take Armes again in a sea of troubles,\n" 44 "And by opposing, end them, to die to sleep;\n" 45 "No more, and by a sleep, to say we end\n" 46 "The heart-ache, and the thousand natural shocks\n" 47 "That flesh is heir to? tis a consumation\n" 48 "Devoutly to be wished. To die to sleep,\n" 49 "To sleepe, perchance to dreame, Aye, there's the rub,\n" 50 "For in that sleep of death what dreams may come\n" 51 "When we haue shuffled off this mortal coil\n" 52 "Must give us pause. There's the respect\n" 53 "That makes calamity of so long life:\n" 54 "For who would bear the Ships and Scorns of time,\n" 55 "The oppressor's wrong, the proud man's Contumely,\n" 56 "The pangs of dispised love, the Law's delay,\n" 57 ; 58 59 /* The known value of the HMAC/SHA3-512 MAC of the above soliloqy */ 60 static const unsigned char expected_output[] = { 61 0x3b, 0x77, 0x5f, 0xf1, 0x4f, 0x9e, 0xb9, 0x23, 62 0x8f, 0xdc, 0xa0, 0x68, 0x15, 0x7b, 0x8a, 0xf1, 63 0x96, 0x23, 0xaa, 0x3c, 0x1f, 0xe9, 0xdc, 0x89, 64 0x11, 0x7d, 0x58, 0x07, 0xe7, 0x96, 0x17, 0xe3, 65 0x44, 0x8b, 0x03, 0x37, 0x91, 0xc0, 0x6e, 0x06, 66 0x7c, 0x54, 0xe4, 0xa4, 0xcc, 0xd5, 0x16, 0xbb, 67 0x5e, 0x4d, 0x64, 0x7d, 0x88, 0x23, 0xc9, 0xb7, 68 0x25, 0xda, 0xbe, 0x4b, 0xe4, 0xd5, 0x34, 0x30, 69 }; 70 71 /* 72 * A property query used for selecting the MAC implementation. 73 */ 74 static const char *propq = NULL; 75 76 int main(void) 77 { 78 int rv = EXIT_FAILURE; 79 OSSL_LIB_CTX *library_context = NULL; 80 EVP_MAC *mac = NULL; 81 EVP_MAC_CTX *mctx = NULL; 82 EVP_MD_CTX *digest_context = NULL; 83 unsigned char *out = NULL; 84 size_t out_len = 0; 85 OSSL_PARAM params[4], *p = params; 86 char digest_name[] = "SHA3-512"; 87 88 library_context = OSSL_LIB_CTX_new(); 89 if (library_context == NULL) { 90 fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n"); 91 goto end; 92 } 93 94 /* Fetch the HMAC implementation */ 95 mac = EVP_MAC_fetch(library_context, "HMAC", propq); 96 if (mac == NULL) { 97 fprintf(stderr, "EVP_MAC_fetch() returned NULL\n"); 98 goto end; 99 } 100 101 /* Create a context for the HMAC operation */ 102 mctx = EVP_MAC_CTX_new(mac); 103 if (mctx == NULL) { 104 fprintf(stderr, "EVP_MAC_CTX_new() returned NULL\n"); 105 goto end; 106 } 107 108 /* The underlying digest to be used */ 109 *p++ = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_DIGEST, digest_name, 110 sizeof(digest_name)); 111 *p = OSSL_PARAM_construct_end(); 112 113 /* Initialise the HMAC operation */ 114 if (!EVP_MAC_init(mctx, key, sizeof(key), params)) { 115 fprintf(stderr, "EVP_MAC_init() failed\n"); 116 goto end; 117 } 118 119 /* Make one or more calls to process the data to be authenticated */ 120 if (!EVP_MAC_update(mctx, data, sizeof(data))) { 121 fprintf(stderr, "EVP_MAC_update() failed\n"); 122 goto end; 123 } 124 125 /* Make a call to the final with a NULL buffer to get the length of the MAC */ 126 if (!EVP_MAC_final(mctx, NULL, &out_len, 0)) { 127 fprintf(stderr, "EVP_MAC_final() failed\n"); 128 goto end; 129 } 130 out = OPENSSL_malloc(out_len); 131 if (out == NULL) { 132 fprintf(stderr, "malloc failed\n"); 133 goto end; 134 } 135 /* Make one call to the final to get the MAC */ 136 if (!EVP_MAC_final(mctx, out, &out_len, out_len)) { 137 fprintf(stderr, "EVP_MAC_final() failed\n"); 138 goto end; 139 } 140 141 printf("Generated MAC:\n"); 142 BIO_dump_indent_fp(stdout, out, out_len, 2); 143 putchar('\n'); 144 145 if (out_len != sizeof(expected_output)) { 146 fprintf(stderr, "Generated MAC has an unexpected length\n"); 147 goto end; 148 } 149 150 if (CRYPTO_memcmp(expected_output, out, sizeof(expected_output)) != 0) { 151 fprintf(stderr, "Generated MAC does not match expected value\n"); 152 goto end; 153 } 154 155 rv = EXIT_SUCCESS; 156 end: 157 if (rv != EXIT_SUCCESS) 158 ERR_print_errors_fp(stderr); 159 /* OpenSSL free functions will ignore NULL arguments */ 160 OPENSSL_free(out); 161 EVP_MD_CTX_free(digest_context); 162 EVP_MAC_CTX_free(mctx); 163 EVP_MAC_free(mac); 164 OSSL_LIB_CTX_free(library_context); 165 return rv; 166 } 167