如何使用ElGamal加密加密文本

Question

我只想知道如何使用ElGamal算法加密文本文件？我使用這種算法得到了整數的加密。請用示例幫助

Answer 1

下面是一個使用Crypto ++的示例。答案是ElGamal encryption example?。

你知道你計劃使用哪種語言或圖書館嗎？

#include <iostream> 
using std::cout; 
using std::cerr; 
using std::endl; 

#include <cryptopp/osrng.h> 
using CryptoPP::AutoSeededRandomPool; 

#include <cryptopp/secblock.h> 
using CryptoPP::SecByteBlock; 

#include <cryptopp/elgamal.h> 
using CryptoPP::ElGamal; 
using CryptoPP::ElGamalKeys; 

#include <cryptopp/cryptlib.h> 
using CryptoPP::DecodingResult; 

int main(int argc, char* argv[]) 
{ 
    //////////////////////////////////////////////// 
    // Generate keys 
    AutoSeededRandomPool rng; 

    cout << "Generating private key. This may take some time..." << endl; 

    ElGamal::Decryptor decryptor; 
    decryptor.AccessKey().GenerateRandomWithKeySize(rng, 512); 
    const ElGamalKeys::PrivateKey& privateKey = decryptor.AccessKey(); 

    ElGamal::Encryptor encryptor(decryptor); 
    const PublicKey& publicKey = encryptor.AccessKey(); 

    //////////////////////////////////////////////// 
    // Secret to protect 
    static const int SECRET_SIZE = 16; 
    SecByteBlock plaintext(SECRET_SIZE); 
    memset(plaintext, 'A', SECRET_SIZE); 

    //////////////////////////////////////////////// 
    // Encrypt 

    // Now that there is a concrete object, we can validate 
    assert(0 != encryptor.FixedMaxPlaintextLength()); 
    assert(plaintext.size() <= encryptor.FixedMaxPlaintextLength()); 

    // Create cipher text space 
    size_t ecl = encryptor.CiphertextLength(plaintext.size()); 
    assert(0 != ecl); 
    SecByteBlock ciphertext(ecl); 

    encryptor.Encrypt(rng, plaintext, plaintext.size(), ciphertext); 

    //////////////////////////////////////////////// 
    // Decrypt 

    // Now that there is a concrete object, we can check sizes 
    assert(0 != decryptor.FixedCiphertextLength()); 
    assert(ciphertext.size() <= decryptor.FixedCiphertextLength()); 

    // Create recovered text space 
    size_t dpl = decryptor.MaxPlaintextLength(ciphertext.size()); 
    assert(0 != dpl); 
    SecByteBlock recovered(dpl); 

    DecodingResult result = decryptor.Decrypt(rng, ciphertext, ciphertext.size(), recovered); 

    // More sanity checks 
    assert(result.isValidCoding); 
    assert(result.messageLength <= decryptor.MaxPlaintextLength(ciphertext.size())); 

    // At this point, we can set the size of the recovered 
    // data. Until decryption occurs (successfully), we 
    // only know its maximum size 
    recovered.resize(result.messageLength); 

    // SecByteBlock is overloaded for proper results below 
    assert(plaintext == recovered); 

    // If the assert fires, we won't get this far. 
    if(plaintext == recovered) 
     cout << "Recovered plain text" << endl; 
    else 
     cout << "Failed to recover plain text" << endl; 

    return !(plaintext == recovered); 
}