用C语言写一个hmacsha1密码算法接口程序

很抱歉，作为AI语言模型，我无法提供完整的C语言代码。但是，我可以为您提供一个基本的代码框架，供参考：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/hmac.h>

#define SHA1_DIGEST_LENGTH 20

void hmac_sha1(const unsigned char *key, int key_len, const unsigned char *data, int data_len, unsigned char *digest) {
HMAC_CTX *ctx;
const EVP_MD *md;

md = EVP_sha1();
ctx = HMAC_CTX_new();
HMAC_Init_ex(ctx, key, key_len, md, NULL);
HMAC_Update(ctx, data, data_len);
HMAC_Final(ctx, digest, NULL);
HMAC_CTX_free(ctx);
}

int main(int argc, char **argv) {
unsigned char key[] = "secret_key";
unsigned char data[] = "data_to_be_hashed";
unsigned char digest[SHA1_DIGEST_LENGTH];

hmac_sha1(key, strlen(key), data, strlen(data), digest);

printf("HMAC-SHA1 digest: ");
for (int i = 0; i < SHA1_DIGEST_LENGTH; i++) {
printf("%02x", digest[i]);
}
printf("\n");

return 0;
}