Question

我正在尝试编写2个不同的函数来使用cryptopp中的AES加密和解密数据。我想将密文作为参数传递给解密函数。然而，在解密功能上，它收到一些特殊符号作为密文＆amp;因此不能正确解密。请帮忙。

// -- AES encryption function ----------
void Security_packetAgent::encryption(char out[])
{ 
    std::string plaintext = out;
    std::string ciphertext = "";

    CryptoPP::AES::Encryption aesEncryption(key, CryptoPP::AES::DEFAULT_KEYLENGTH);
    CryptoPP::CBC_Mode_ExternalCipher::Encryption cbcEncryption( aesEncryption, iv );

    CryptoPP::StreamTransformationFilter stfEncryptor(cbcEncryption, new CryptoPP::StringSink( ciphertext ) );
    stfEncryptor.Put( reinterpret_cast<const unsigned char*>( plaintext.c_str() ), plaintext.length() + 1 );
    stfEncryptor.MessageEnd();

    std::cout << "Cipher Text (" << ciphertext.size() << " bytes)" << std::endl;

    for( int i = 0; i < ciphertext.size(); i++ )
    {
        std::cout << "0x" << std::hex << (0xFF & static_cast<byte>(ciphertext[i])) << " ";
    }

    std::cout<<"\nMessage encrypted ...";
    std::cout << std::endl << std::endl;
    sprintf(out, "%s", ciphertext.c_str());
    printf("Final Data: %s : %s ", out, reinterpret_cast<const unsigned char*>(ciphertext.c_str()));
}

// ---- AES decryption  ------------------
void Security_packetAgent::decryption(char out[])
{ 
    cout<<"\nCipher recieved: "<<out;
    std::cout<<"\nEntered decryption ..";
    std::string ciphertext = out;
    std::string decryptedtext;

    cout<<"\nCipher recieved: "<<reinterpret_cast<const unsigned char*>( ciphertext.c_str());
    CryptoPP::AES::Decryption aesDecryption(key, CryptoPP::AES::DEFAULT_KEYLENGTH);
    CryptoPP::CBC_Mode_ExternalCipher::Decryption cbcDecryption( aesDecryption, iv );

    CryptoPP::StreamTransformationFilter stfDecryptor(cbcDecryption, new CryptoPP::StringSink( decryptedtext ) );
    stfDecryptor.Put( reinterpret_cast<const unsigned char*>( ciphertext.c_str() ), ciphertext.size() );
    stfDecryptor.MessageEnd();

    std::cout << "Decrypted Text: " << std::endl;
    std::cout << decryptedtext;
    std::cout << std::endl << std::endl;    
}

Answer 1

如果std::string指向不是文本字符串的内容（例如加密数据），则不应该从char*构建char*。

std::string ciphertext = out;

ciphertext的构造一旦到达0字节就会停止从out复制。相反，您还需要传递加密数据的长度并使用std::string(const char* data, size_t size)构造函数。

std::string ciphertext(out, outSize);

或者，您也可以使用带有开始和结束迭代器的构造函数。

将AES密文作为参数传递

1 个答案: