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openssl3.2 - 官方demo学习 - mac - gmac.c

概述

使用GMAC算法, 设置参数(指定加密算法 e.g. AES-128-GCM, 设置iv)
用key执行初始化, 然后对明文生成MAC数据
官方注释给出建议, key, iv最好不要硬编码出现在程序中

笔记

/*!
\file gmac.c
\note openssl3.2 - 官方demo学习 - mac - gmac.c
使用GMAC算法, 设置参数(指定加密算法 e.g. AES-128-GCM, 设置iv)
用key执行初始化, 然后对明文生成MAC数据
*//** Copyright 2021-2023 The OpenSSL Project Authors. All Rights Reserved.** Licensed under the Apache License 2.0 (the "License").  You may not use* this file except in compliance with the License.  You can obtain a copy* in the file LICENSE in the source distribution or at* https://www.openssl.org/source/license.html*/#include <stdio.h>
#include <stdlib.h>
#include <openssl/core_names.h>
#include <openssl/evp.h>
#include <openssl/params.h>
#include <openssl/err.h>#include "my_openSSL_lib.h"/** Taken from NIST's GCM Test Vectors* http://csrc.nist.gov/groups/STM/cavp/*//** Hard coding the key into an application is very bad.* It is done here solely for educational purposes.*/
static unsigned char key[] = {0x77, 0xbe, 0x63, 0x70, 0x89, 0x71, 0xc4, 0xe2,0x40, 0xd1, 0xcb, 0x79, 0xe8, 0xd7, 0x7f, 0xeb
};/** The initialisation vector (IV) is better not being hard coded too.* Repeating password/IV pairs compromises the integrity of GMAC.* The IV is not considered secret information and is safe to store with* an encrypted password.*/
static unsigned char iv[] = {0xe0, 0xe0, 0x0f, 0x19, 0xfe, 0xd7, 0xba,0x01, 0x36, 0xa7, 0x97, 0xf3
};static unsigned char data[] = {0x7a, 0x43, 0xec, 0x1d, 0x9c, 0x0a, 0x5a, 0x78,0xa0, 0xb1, 0x65, 0x33, 0xa6, 0x21, 0x3c, 0xab
};static const unsigned char expected_output[] = {0x20, 0x9f, 0xcc, 0x8d, 0x36, 0x75, 0xed, 0x93,0x8e, 0x9c, 0x71, 0x66, 0x70, 0x9d, 0xd9, 0x46
};/** A property query used for selecting the GMAC implementation and the* underlying GCM mode cipher.*/
static char* propq = NULL;int main(int argc, char** argv)
{int ret = EXIT_FAILURE;EVP_MAC* _evp_mac = NULL;EVP_MAC_CTX* _evp_mac_ctx = NULL;unsigned char out[16];OSSL_PARAM _ossl_param_ary[4], * p_ossl_param = _ossl_param_ary;OSSL_LIB_CTX* _ossl_lib_ctx = NULL;size_t out_len = 0;_ossl_lib_ctx = OSSL_LIB_CTX_new();if (_ossl_lib_ctx == NULL) {fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");goto end;}/* Fetch the GMAC implementation */_evp_mac = EVP_MAC_fetch(_ossl_lib_ctx, "GMAC", propq);if (_evp_mac == NULL) {fprintf(stderr, "EVP_MAC_fetch() returned NULL\n");goto end;}/* Create a context for the GMAC operation */_evp_mac_ctx = EVP_MAC_CTX_new(_evp_mac);if (_evp_mac_ctx == NULL) {fprintf(stderr, "EVP_MAC_CTX_new() returned NULL\n");goto end;}/* GMAC requires a GCM mode cipher to be specified */*p_ossl_param++ = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_CIPHER,"AES-128-GCM", 0);/** If a non-default property query is required when fetching the GCM mode* cipher, it needs to be specified too.*/if (propq != NULL)*p_ossl_param++ = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_PROPERTIES,propq, 0);/* Set the initialisation vector (IV) */*p_ossl_param++ = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_IV,iv, sizeof(iv));*p_ossl_param = OSSL_PARAM_construct_end();/* Initialise the GMAC operation */if (!EVP_MAC_init(_evp_mac_ctx, key, sizeof(key), _ossl_param_ary)) {fprintf(stderr, "EVP_MAC_init() failed\n");goto end;}/* Make one or more calls to process the data to be authenticated */if (!EVP_MAC_update(_evp_mac_ctx, data, sizeof(data))) {fprintf(stderr, "EVP_MAC_update() failed\n");goto end;}/* Make one call to the final to get the MAC */if (!EVP_MAC_final(_evp_mac_ctx, out, &out_len, sizeof(out))) {fprintf(stderr, "EVP_MAC_final() failed\n");goto end;}printf("Generated MAC:\n");BIO_dump_indent_fp(stdout, out, (int)out_len, 2);putchar('\n');if (out_len != sizeof(expected_output)) {fprintf(stderr, "Generated MAC has an unexpected length\n");goto end;}if (CRYPTO_memcmp(expected_output, out, sizeof(expected_output)) != 0) {fprintf(stderr, "Generated MAC does not match expected value\n");goto end;}ret = EXIT_SUCCESS;
end:EVP_MAC_CTX_free(_evp_mac_ctx);EVP_MAC_free(_evp_mac);OSSL_LIB_CTX_free(_ossl_lib_ctx);if (ret != EXIT_SUCCESS)ERR_print_errors_fp(stderr);return ret;
}

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