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Raw RSA encryption and decryption.
// g++ rsa.cpp -o rsa -lcryptopp
#include <iostream>
#include <cryptopp/rsa.h>
#include <cryptopp/integer.h>
#include <cryptopp/osrng.h>
int main(){
// Keys
CryptoPP::Integer n("0xbeaadb3d839f3b5f"), e("0x11"), d("0x21a5ae37b9959db9");
CryptoPP::RSA::PrivateKey privKey;
privKey.Initialize(n, e, d);
CryptoPP::RSA::PublicKey pubKey;
pubKey.Initialize(n, e);
// Encryption
std::string message = "secret";
CryptoPP::Integer m((const byte *)message.data(), message.size());
std::cout << "m: " << m << std::endl;
// m: 126879297332596.
CryptoPP::Integer c = pubKey.ApplyFunction(m);
std::cout << "c: " << std::hex << c << std::endl;
// c: 3f47c32e8e17e291h
// Decryption
CryptoPP::AutoSeededRandomPool prng;
CryptoPP::Integer r = privKey.CalculateInverse(prng, c);
std::cout << "r: " << std::hex << r << std::endl;
// r: 736563726574h
std::string recovered;
recovered.resize(r.MinEncodedSize());
r.Encode((byte *)recovered.data(), recovered.size());
std::cout << "recovered: " << recovered << std::endl;
// recovered: secret
return 0;
}
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