openssl 生成摘要、签名和验签接口使用

青旅半醒 2022-09-14 08:50 310阅读 0赞

1、生成摘要

int getDigest(const char* source, int source_len, unsigned char *digest_data, unsigned int *digest_len)
    {
    	EVP_MD_CTX *mdctx;
    	if((mdctx = EVP_MD_CTX_create()) == NULL) {
    		return -1;
    	}
        
    	if(1 != EVP_DigestInit_ex(mdctx, EVP_sha256(), NULL)) {
    		return -1;
    	}
    
    	if(1 != EVP_DigestUpdate(mdctx, source, source_len)) {
    		return -1;
    	}
        
    	if(1 != EVP_DigestFinal_ex(mdctx, digest_data, digest_len)) {
    		return -1;
    	}
       
    	EVP_MD_CTX_destroy(mdctx);
    	
    	return 0;
    }

2、签名

int signData(EVP_PKEY * key, unsigned char *data, unsigned int data_len, 
                         unsigned char *sign, unsigned int *sign_len)
    {
        EVP_MD_CTX *ctx = EVP_MD_CTX_create();
    	const EVP_MD* digestAlg = EVP_sha256();
        
    	if(1 != EVP_SignInit(ctx, digestAlg))
    		goto err_exit;  
    
    	if(1 != EVP_SignUpdate(ctx, data, data_len))
    		goto err_exit;
    
    	if(1 != EVP_SignFinal(ctx, sign, sign_len, key))
    		goto err_exit;
    
        EVP_MD_CTX_free(ctx);
    
        return 0;
    err_exit:
        EVP_MD_CTX_free(ctx);
        return -1;
        
    }

3、验签

int verify(EVP_PKEY * key, unsigned char * sign_data, unsigned int sign_data_len, 
                unsigned char * original, unsigned int original_len)
    {
        EVP_MD_CTX *ctx = EVP_MD_CTX_create();
    	const EVP_MD* digestAlg = EVP_sha256();
    
    	if(1 != EVP_VerifyInit(ctx, digestAlg))
    		goto err_exit; 
    
    	if(1 != EVP_VerifyUpdate(ctx, original, original_len))
    		goto err_exit;    
    
    	if(1 != EVP_VerifyFinal(ctx, sign_data, sign_data_len, key))
    		goto err_exit; 
    
    	EVP_MD_CTX_free(ctx);
    
        return 0;
    err_exit:
        EVP_MD_CTX_free(ctx);
        return -1;
    }

二、demo

int main(void)
    {	
        FILE *sfd = fopen("/home/opensslapi/pfx_pri.pem", "r");
        FILE *pfd = fopen("/home/opensslapi/pfx_pub.pem", "r");
        EVP_PKEY *sk = PEM_read_PrivateKey(sfd, NULL, NULL, NULL);
        EVP_PKEY *pk = PEM_read_PUBKEY(pfd, NULL, NULL, NULL);
    
        fclose(sfd);
        fclose(pfd);
    
    	char src_data[64] = "123qwet";
        unsigned int sign_len = 0, digest_len = 0;
        unsigned char sign[512] = {0};
        unsigned char hash_str[512] = {0};
    
    
    	getDigest(src_data, strlen(src_data), hash_src, &digest_len);
    
        signData(sk, src_data, strlen(src_data), sign, &sign_len);
        
        if(0 == verify(pk, sign, sign_len, src_data, strlen(src_data)))
            printf("verify success\n");
        else
            printf("verify failed\n");
    
    	EVP_PKEY_free(sk);
    	EVP_PKEY_free(pk);
        return 0;
    }