hmac-sha1加密算法C源码示例

超、凢脫俗 2022-08-01 16:52 172阅读 0赞

HMAC: Hash-based Message Authentication Code，即基于Hash的消息鉴别码

在各大开放平台大行其道的互联网开发潮流中，调用各平台的API接口过程中，无一例外都会用到计算签名值(sig值)。而在各种计算签名的方法中，经常被采用的就是HMAC-SHA1，现对HMAC-SHA1做一个简单的介绍： HMAC，散列消息鉴别码，基于密钥的Hash算法认证协议。 实现原理为： 利用已经公开的Hash函数和私有的密钥，来生成固定长度的消息鉴别码； SHA1、MD5等Hash算法是比较常用的不可逆Hash签名计算方法； BASE64，将任意序列的8字节字符转换为人眼无法直接识别的符号编码的一种方法； 
     
      
    
     
      
     
      
       
      相关依赖库是openssl，安装方法如下：
     
      
     
      
       
      apt-get install openssl   //Ubuntu 14.04
     
      
     
      
       
      yum -y install openssl-devel    //centos 
     
      
     下面提供两个源码示例: 例子一:
     //gcc -g hmac_sha1_demo3.c -o hmac_sha1_demo3 -lcrypto -std=c99
    
    #include <stdio.h>
    #include <string.h>
    #include <openssl/hmac.h>
    
    int main()
    {
        // The key to hash
        char key[] = "012345678";
    
        // The data that we're going to hash using HMAC
        char data[] = "hello world";
    
        unsigned char digest[EVP_MAX_MD_SIZE] = {'\0'};
        unsigned int digest_len = 0;
    
        // Using sha1 hash engine here.
        // You may use other hash engines. e.g EVP_md5(), EVP_sha224, EVP_sha512, etc
        HMAC(EVP_sha1(), key, strlen(key), (unsigned char*)data, strlen(data), digest, &digest_len);
        printf("%s, len %u\n", digest, digest_len);
    
        // Be careful of the length of string with the choosen hash engine. SHA1 produces a 20-byte hash value which rendered as 40 characters.
        // Change the length accordingly with your choosen hash engine
        char mdString[41] = {'\0'};
        for(int i = 0; i < 20; i++)
             sprintf(&mdString[i*2], "%02x", (unsigned int)digest[i]);
    
        printf("HMAC digest: %s\n", mdString);
    
        return 0;
    }
    例子二: //gcc -g hmac_sha1_demo2.c -o hmac_sha1_demo2 -lcrypto --std=c99
    
    #include <stdio.h>
    #include <string.h>
    #include <openssl/hmac.h>
    
    int main() {
        // The secret key for hashing
        const char key[] = "012345678";
    
        // The data that we're going to hash
        char data[] = "hello world";
    
        // Be careful of the length of string with the choosen hash engine. SHA1 needed 20 characters.
        // Change the length accordingly with your choosen hash engine.
        unsigned char* result;
        unsigned int len = 20;
    
        result = (unsigned char*)malloc(sizeof(char) * len);
    
        HMAC_CTX ctx;
        HMAC_CTX_init(&ctx);
    
        // Using sha1 hash engine here.
        // You may use other hash engines. e.g EVP_md5(), EVP_sha224, EVP_sha512, etc
        HMAC_Init_ex(&ctx, key, strlen(key), EVP_sha1(), NULL);
        HMAC_Update(&ctx, (unsigned char*)&data, strlen(data));
        HMAC_Final(&ctx, result, &len);
        HMAC_CTX_cleanup(&ctx);
    
        printf("HMAC digest: ");
    
        for (int i = 0; i != len; i++)
            printf("%02x", (unsigned int)result[i]);
    
        printf("\n");
    
        free(result);
    
        return 0;
    }运行截图:
    
    
    参考文献: [1].http://www.askyb.com/cpp/openssl-hmac-hasing-example-in-cpp/