Question

我正在使用Example of AES using Crypto++。我想用这个密钥加密：

std::string key = "mykey";

为密钥分配内存

byte key[ CryptoPP::AES::DEFAULT_KEYLENGTH ], iv[ CryptoPP::AES::BLOCKSIZE ];
memset( key, 0x00, CryptoPP::AES::DEFAULT_KEYLENGTH );
memset( iv, 0x00, CryptoPP::AES::BLOCKSIZE );

加密：

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

如何将 std :: string 类型的密钥传递给 aesEncryption 函数？

Answer 1

以下是解决方案：

std::string sKey = "mykey";

if(CryptoPP::AES::DEFAULT_KEYLENGTH < sKey.size())
    sKey = sKey.substr(0, CryptoPP::AES::DEFAULT_KEYLENGTH); // chop if too long
else if(CryptoPP::AES::DEFAULT_KEYLENGTH > sKey.size())
    sKey += std::string(CryptoPP::AES::DEFAULT_KEYLENGTH - sKey.size(), '*'); // pad

memcpy(key, sKey.c_str(), CryptoPP::AES::DEFAULT_KEYLENGTH);

Answer 2

这是另一个使用sha256和密码cat的示例！

#include <iomanip>
#include <iostream>

#include <cryptopp/modes.h>
#include <cryptopp/aes.h>
#include <cryptopp/filters.h>
#include <cryptopp/sha.h>
#include <cryptopp/hex.h>


int main(int argc, char* argv[]) {



    CryptoPP::SHA256 hash;
    CryptoPP::byte digest[CryptoPP::SHA256::DIGESTSIZE];
    std::string message = "cat";

    hash.CalculateDigest(digest, (CryptoPP::byte*)message.c_str(), message.length());

    CryptoPP::HexEncoder encoder;
    std::string sKey;
    encoder.Attach(new CryptoPP::StringSink(sKey));
    encoder.Put(digest, sizeof(digest));
    encoder.MessageEnd();

    CryptoPP::byte key[CryptoPP::AES::MAX_KEYLENGTH]; //16 Bytes MAXKEYLENGTH 32 BYTES(SHA 256)
    CryptoPP::byte  iv[CryptoPP::AES::BLOCKSIZE]; 
    memcpy(key, sKey.c_str(), CryptoPP::AES::MAX_KEYLENGTH);;
    memset(iv, 0x00, CryptoPP::AES::BLOCKSIZE);

    //
    // String and Sink setup
    //
    std::string plaintext = "Now is the time for all good men to come to the aide...";
    std::string ciphertext;
    std::string decryptedtext;

    //
    // Dump Plain Text
    //
    std::cout << "Plain Text (" << plaintext.size() << " bytes)" << std::endl;
    std::cout << plaintext;
    std::cout << std::endl << std::endl;

    //
    // Create Cipher Text
    //

    CryptoPP::AES::Encryption aesEncryption(key, CryptoPP::AES::MAX_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());
    stfEncryptor.MessageEnd();

    //
    // Dump Cipher Text
    //
    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<CryptoPP::byte>(ciphertext[i])) << " ";
    }

    std::cout << std::endl << std::endl;

    //
    // Decrypt
    //
    CryptoPP::AES::Decryption aesDecryption(key, CryptoPP::AES::MAX_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();

    //
    // Dump Decrypted Text
    //
    std::cout << "Decrypted Text: " << std::endl;
    std::cout << decryptedtext;
    std::cout << std::endl << std::endl;

    return 0;

}

在Crypto ++中使用带有AES加密的密钥的std :: string

2 个答案: