linux 签名 c++

#include <openssl/ec.h>
#include <openssl/pem.h>
#include <openssl/evp.h>
#include <openssl/rand.h>
#include <iostream>

void generate_key_pair() {
    EC_KEY *key = EC_KEY_new_by_curve_name(NID_secp256k1);
    if (!key) {
        std::cerr << "Failed to create EC key" << std::endl;
        return;
    }

    if (EC_KEY_generate_key(key) != 1) {
        std::cerr << "Failed to generate key pair" << std::endl;
        EC_KEY_free(key);
        return;
    }

    FILE *pub_fp = fopen("public_key.pem", "w");
    FILE *priv_fp = fopen("private_key.pem", "w");

    PEM_write_EC_PUBKEY(pub_fp, key);
    PEM_write_ECPrivateKey(priv_fp, key);

    fclose(pub_fp);
    fclose(priv_fp);
    EC_KEY_free(key);
}

void sign_data(const std::string &data) {
    FILE *priv_fp = fopen("private_key.pem", "r");
    if (!priv_fp) {
        std::cerr << "Failed to open private key file" << std::endl;
        return;
    }

    EC_KEY *key = PEM_read_ECPrivateKey(priv_fp, NULL, NULL, NULL);
    fclose(priv_fp);

    if (!key) {
        std::cerr << "Failed to read private key" << std::endl;
        return;
    }

    unsigned char digest[EVP_MAX_MD_SIZE];
    unsigned int digest_len;
    EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();
    EVP_DigestInit_ex(md_ctx, EVP_sha256(), NULL);
    EVP_DigestUpdate(md_ctx, data.c_str(), data.size());
    EVP_DigestFinal_ex(md_ctx, digest, &digest_len);
    EVP_MD_CTX_free(md_ctx);

    unsigned char signature[72];
    unsigned int signature_len;
    ECDSA_sign(0, digest, digest_len, signature, &signature_len, key);

    FILE *sig_fp = fopen("signature.bin", "wb");
    fwrite(signature, 1, signature_len, sig_fp);
    fclose(sig_fp);

    EC_KEY_free(key);
}

bool verify_signature(const std::string &data) {
    FILE *pub_fp = fopen("public_key.pem", "r");
    if (!pub_fp) {
        std::cerr << "Failed to open public key file" << std::endl;
        return false;
    }

    EC_KEY *key = PEM_read_EC_PUBKEY(pub_fp, NULL, NULL, NULL);
    fclose(pub_fp);

    if (!key) {
        std::cerr << "Failed to read public key" << std::endl;
        return false;
    }

    FILE *sig_fp = fopen("signature.bin", "rb");
    unsigned char signature[72];
    unsigned int signature_len = fread(signature, 1, sizeof(signature), sig_fp);
    fclose(sig_fp);

    unsigned char digest[EVP_MAX_MD_SIZE];
    unsigned int digest_len;
    EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();
    EVP_DigestInit_ex(md_ctx, EVP_sha256(), NULL);
    EVP_DigestUpdate(md_ctx, data.c_str(), data.size());
    EVP_DigestFinal_ex(md_ctx, digest, &digest_len);
    EVP_MD_CTX_free(md_ctx);

    int result = ECDSA_verify(0, digest, digest_len, signature, signature_len, key);
    EC_KEY_free(key);

    return result == 1;
}