openssl编程之hmac算法编程示例

int openssl_hash() {{// 输入参数const char* key = "xiaohai";const char* data = "xiaohai";unsigned int hmac_len;// 计算HMACunsigned char* result = HMAC(EVP_sha256(),                  // 算法key, strlen(key),              // 密钥(unsigned char*)data, strlen(data), // 消息NULL, &hmac_len                // 输出参数);// 打印结果（16进制）printf("HMAC-SHA256: ");for (int i = 0; i < hmac_len; i++) {printf("%02x", result[i]);}printf("\n");}{unsigned char buf[4096];unsigned char hmac[32];unsigned int hmac_len = 32;HMAC_CTX* ctx = HMAC_CTX_new();HMAC_Init_ex(ctx, "xiaohai", strlen("xiaohai"), EVP_sha256(), NULL);HMAC_Update(ctx, (unsigned char *)"xiaohai", strlen("xiaohai"));HMAC_Final(ctx, hmac, &hmac_len);HMAC_CTX_free(ctx);// 打印结果（16进制）printf("HMAC-SHA256: ");for (int i = 0; i < hmac_len; i++) {printf("%02x", hmac[i]);}printf("\n");}return 0;
}