// 公钥加密

std::string rsa_pub_encrypt(const std::string &clearText,  std::string &pubKey)

{

    std::string strRet;

    BIO *keybio = BIO_new_mem_buf((unsigned char *)pubKey.c_str(), -);

    //keybio = BIO_new_mem_buf((unsigned char *)strPublicKey.c_str(), -1);

    // 此处有三种方法

    // 1, 读取内存里生成的密钥对，再从内存生成rsa

    // 2, 读取磁盘里生成的密钥对文本文件，在从内存生成rsa

    // 3，直接从读取文件指针生成rsa

    //RSA* pRSAPublicKey = RSA_new();

    RSA* rsa = RSA_new();

    rsa = PEM_read_bio_RSAPublicKey(keybio, &rsa, NULL, NULL);

    if (!rsa)

    {

            BIO_free_all(keybio);

            return std::string("");

    }

    int len = RSA_size(rsa);

    //int len = 1028;

    char *encryptedText = (char *)malloc(len + );

    memset(encryptedText, , len + );  

    // 加密函数

    int ret = RSA_public_encrypt(clearText.length(), (const unsigned char*)clearText.c_str(), (unsigned char*)encryptedText, rsa, RSA_PKCS1_PADDING);

    if (ret >= )

        strRet = std::string(encryptedText, ret);  

    // 释放内存

    free(encryptedText);

    BIO_free_all(keybio);

    RSA_free(rsa);

    return strRet;

}  

// 私钥解密

std::string rsa_pri_decrypt(const std::string &cipherText, const std::string &priKey)

{

    std::string strRet;

    RSA *rsa = RSA_new();

    BIO *keybio;

    keybio = BIO_new_mem_buf((unsigned char *)priKey.c_str(), -);  

    // 此处有三种方法

    // 1, 读取内存里生成的密钥对，再从内存生成rsa

    // 2, 读取磁盘里生成的密钥对文本文件，在从内存生成rsa

    // 3，直接从读取文件指针生成rsa

    rsa = PEM_read_bio_RSAPrivateKey(keybio, &rsa, NULL, NULL);  

    int len = RSA_size(rsa);

    char *decryptedText = (char *)malloc(len + );

    memset(decryptedText, , len + );  

    // 解密函数

    int ret = RSA_private_decrypt(cipherText.length(), (const unsigned char*)cipherText.c_str(), (unsigned char*)decryptedText, rsa, RSA_PKCS1_PADDING);

    if (ret >= )

        strRet = std::string(decryptedText, ret);  

    // 释放内存

    free(decryptedText);

    BIO_free_all(keybio);

    RSA_free(rsa);  

    return strRet;

}