rsa数字签名算法c++实现

以下是一个基于 OpenSSL 库的 RSA 数字签名实现的示例代码： #include <stdio.h> #include <stdlib.h> #include <string.h> #include <openssl/rsa.h> #include <openssl/pem.h> int main(int argc, char *argv[]) { if (argc != 4) { printf("Usage: %s <private_key_file> <input_file> <signature_file>\n", argv[0]); return 1; } const char *privkey_path = argv[1]; const char *input_path = argv[2]; const char *sig_path = argv[3]; // 读取私钥文件 FILE *privkey_file = fopen(privkey_path, "r"); if (!privkey_file) { perror("Failed to open private key file"); return 1; } RSA *rsa = PEM_read_RSAPrivateKey(privkey_file, NULL, NULL, NULL); fclose(privkey_file); if (!rsa) { fprintf(stderr, "Failed to read private key file\n"); return 1; } // 读取输入文件 FILE *input_file = fopen(input_path, "rb"); if (!input_file) { perror("Failed to open input file"); return 1; } fseek(input_file, 0, SEEK_END); long input_size = ftell(input_file); fseek(input_file, 0, SEEK_SET); char *input_data = malloc(input_size); fread(input_data, input_size, 1, input_file); fclose(input_file); // 计算输入文件的哈希值 unsigned char hash[SHA256_DIGEST_LENGTH]; SHA256((const unsigned char *)input_data, input_size, hash); // 签名哈希值 unsigned int sig_len; unsigned char *sig_data = malloc(RSA_size(rsa)); if (!RSA_sign(NID_sha256, hash, sizeof(hash), sig_data, &sig_len, rsa)) { fprintf(stderr, "Failed to sign hash\n"); return 1; } // 写入签名文件 FILE *sig_file = fopen(sig_path, "wb"); if (!sig_file) { perror("Failed to open signature file"); return 1; } fwrite(sig_data, sig_len, 1, sig_file); fclose(sig_file); printf("Signature generated successfully.\n"); RSA_free(rsa); free(input_data); free(sig_data); return 0; } 在此示例中，我们使用 OpenSSL 库计算 SHA256 哈希值，然后使用 RSA 签名哈希值。请注意，在实际应用中，您可能需要使用更安全的哈希算法和更复杂的签名方案。另外，请确保您的私钥文件在存储和传输时得到适当的保护。

RSA是一种非对称加密算法，可以用于数字签名。下面是一个使用C++实现RSA数字签名的例子： ```cpp #include <iostream> #include <string> #include <openssl/rsa.h> #include <openssl/pem.h> using namespace std; int main() { // 生成RSA密钥对 RSA *keypair = RSA_generate_key(2048, RSA_F4, NULL, NULL); if (keypair == NULL) { cout << "Failed to generate RSA key pair." << endl; return 1; } // 获取私钥和公钥 BIO *pri = BIO_new(BIO_s_mem()); BIO *pub = BIO_new(BIO_s_mem()); PEM_write_bio_RSAPrivateKey(pri, keypair, NULL, NULL, 0, NULL, NULL); PEM_write_bio_RSAPublicKey(pub, keypair); // 从BIO中读取私钥和公钥 char *pri_key = NULL; char *pub_key = NULL; long pri_len = BIO_get_mem_data(pri, &pri_key); long pub_len = BIO_get_mem_data(pub, &pub_key); // 签名 string message = "Hello, world!"; unsigned char *sig = new unsigned char[RSA_size(keypair)]; unsigned int sig_len; RSA_sign(NID_sha256, (const unsigned char *)message.c_str(), message.length(), sig, &sig_len, keypair); // 验证签名 int result = RSA_verify(NID_sha256, (const unsigned char *)message.c_str(), message.length(), sig, sig_len, keypair); if (result == 1) { cout << "Signature verified." << endl; } else { cout << "Signature verification failed." << endl; } // 输出私钥和公钥 cout << "Private key:" << endl << string(pri_key, pri_len) << endl; cout << "Public key:" << endl << string(pub_key, pub_len) << endl; // 释放资源 RSA_free(keypair); BIO_free_all(pri); BIO_free_all(pub); delete[] sig; return 0; } ```