rsa加密解密算法c++语言

RSA是一种非对称加密算法，下面给出RSA加密解密算法的C++代码实现。

1. 生成RSA密钥对

#include <openssl/rsa.h>
#include <openssl/pem.h>

void generateRSAKeyPair(RSA *&publicKey, RSA *&privateKey) {
    // 随机数种子
    srand((unsigned)time(NULL));
    // 生成RSA密钥对
    int bits = 1024;  // 密钥长度
    unsigned long e = RSA_F4;
    publicKey = RSA_new();
    privateKey = RSA_new();
    BIGNUM *bn = BN_new();
    BN_set_word(bn, e);
    RSA_generate_key_ex(publicKey, bits, bn, NULL);
    RSA_generate_key_ex(privateKey, bits, bn, NULL);
    BN_free(bn);
}

2. RSA公钥加密

#include <openssl/rsa.h>
#include <openssl/pem.h>

std::string rsaPublicKeyEncrypt(RSA *publicKey, const std::string &plainText) {
    int rsaSize = RSA_size(publicKey);
    int blockSize = rsaSize - 11;
    int blockNum = (plainText.length() + blockSize - 1) / blockSize;
    std::string cipherText;
    for (int i = 0; i < blockNum; i++) {
        std::string plainBlock = plainText.substr(i * blockSize, blockSize);
        char *cipherBlock = new char[rsaSize];
        int len = RSA_public_encrypt(plainBlock.length(), (const unsigned char*)plainBlock.c_str(), (unsigned char*)cipherBlock, publicKey, RSA_PKCS1_PADDING);
        cipherText.append(cipherBlock, len);
        delete[] cipherBlock;
    }
    return cipherText;
}

3. RSA私钥解密

#include <openssl/rsa.h>
#include <openssl/pem.h>

std::string rsaPrivateKeyDecrypt(RSA *privateKey, const std::string &cipherText) {
    int rsaSize = RSA_size(privateKey);
    int blockSize = rsaSize;
    int blockNum = (cipherText.length() + blockSize - 1) / blockSize;
    std::string plainText;
    for (int i = 0; i < blockNum; i++) {
        std::string cipherBlock = cipherText.substr(i * blockSize, blockSize);
        char *plainBlock = new char[rsaSize];
        int len = RSA_private_decrypt(cipherBlock.length(), (const unsigned char*)cipherBlock.c_str(), (unsigned char*)plainBlock, privateKey, RSA_PKCS1_PADDING);
        plainText.append(plainBlock, len);
        delete[] plainBlock;
    }
    return plainText;
}

使用时，可以先生成RSA密钥对，然后使用公钥加密数据，再使用私钥解密数据。具体代码如下：

// 生成RSA密钥对
RSA *publicKey = NULL, *privateKey = NULL;
generateRSAKeyPair(publicKey, privateKey);

// 使用公钥加密数据
std::string plainText = "Hello, RSA!";
std::string cipherText = rsaPublicKeyEncrypt(publicKey, plainText);

// 使用私钥解密数据
std::string decryptedText = rsaPrivateKeyDecrypt(privateKey, cipherText);
std::cout << decryptedText << std::endl;

// 释放RSA密钥对
RSA_free(publicKey);
RSA_free(privateKey);