openssl3.2 – 官方demo学习 – mac

本文介绍: MAC算法为 SIPHASH, 设置参数(C-rounds, D-rounds, 也可以不设置, 有默认值)用key初始化MAC算法, 算明文的MAC值。

文章目录

openssl3.2 – 官方demo学习 – mac – siphash.c

概述

MAC算法为 SIPHASH, 设置参数(C-rounds, D-rounds, 也可以不设置, 有默认值)
用key初始化MAC算法, 算明文的MAC值

笔记

/*!
file siphash.c
note
openssl3.2 - 官方demo学习 - mac - siphash.c
MAC算法为 SIPHASH, 设置参数(C-rounds, D-rounds, 也可以不设置, 有默认值)
用key初始化MAC算法, 算明文的MAC值
*/

/*
 * 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 the test vector from the paper "SipHash: a fast short-input PRF".
  * https://www.aumasson.jp/siphash/siphash.pdf
  */

  /*
   * Hard coding the key into an application is very bad.
   * It is done here solely for educational purposes.
   */
static unsigned char key[] = {
	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
};

static unsigned char data[] = {
	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e
};

static const unsigned char expected_output[] = {
	0xe5, 0x45, 0xbe, 0x49, 0x61, 0xca, 0x29, 0xa1
};

/*
 * A property query used for selecting the SIPHASH implementation.
 */
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[8];
	OSSL_PARAM params[4], * p = params;
	OSSL_LIB_CTX* _ossl_lib_ctx = NULL;
	unsigned int digest_len = 8, c_rounds = 2, d_rounds = 4;
	size_t out_len = 0;

	_ossl_lib_ctx = OSSL_LIB_CTX_new();
	if (_ossl_lib_ctx == NULL) {
		fprintf(stderr, "OSSL_LIB_CTX_new() returned NULLn");
		goto end;
	}

	/* Fetch the SipHash implementation */
	_evp_mac = EVP_MAC_fetch(_ossl_lib_ctx, "SIPHASH", propq);
	if (_evp_mac == NULL) {
		fprintf(stderr, "EVP_MAC_fetch() returned NULLn");
		goto end;
	}

	/* Create a context for the SipHash operation */
	_evp_mac_ctx = EVP_MAC_CTX_new(_evp_mac);
	if (_evp_mac_ctx == NULL) {
		fprintf(stderr, "EVP_MAC_CTX_new() returned NULLn");
		goto end;
	}

	/* SipHash can support either 8 or 16-byte digests. */
	*p++ = OSSL_PARAM_construct_uint(OSSL_MAC_PARAM_SIZE, &digest_len);

	/*
	 * The number of C-rounds and D-rounds is configurable. Standard SipHash
	 * uses values of 2 and 4 respectively. The following lines are unnecessary
	 * as they set the default, but demonstrate how to change these values.
	 */
	*p++ = OSSL_PARAM_construct_uint(OSSL_MAC_PARAM_C_ROUNDS, &c_rounds);
	*p++ = OSSL_PARAM_construct_uint(OSSL_MAC_PARAM_D_ROUNDS, &d_rounds);

	*p = OSSL_PARAM_construct_end();

	/* Initialise the SIPHASH operation */
	if (!EVP_MAC_init(_evp_mac_ctx, key, sizeof(key), params)) {
		fprintf(stderr, "EVP_MAC_init() failedn");
		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() failedn");
		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() failedn");
		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 lengthn");
		goto end;
	}

	if (CRYPTO_memcmp(expected_output, out, sizeof(expected_output)) != 0) {
		fprintf(stderr, "Generated MAC does not match expected valuen");
		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;
}