#include <rsa.h>
#include <osrng.h>
#include <pssr.h>
#include <iostream>

using namespace CryptoPP;
using namespace std;

class MyPrivKey : public RSA::PrivateKey {
public:
    template<typename... Args>
    MyPrivKey(Args&&... args) : RSA::PrivateKey(std::forward<Args>(args)...) {}

    Integer CalculateInverse(RandomNumberGenerator &rng, const Integer &x) const override {
      // Never called :'(
      return RSA::PrivateKey::CalculateInverse(rng, x);
    }
};


int main() {

  ///////////////////////////////////////
  // Pseudo Random Number Generator
  AutoSeededRandomPool rng;

  ///////////////////////////////////////
  // Generate Parameters
  InvertibleRSAFunction params;
  params.GenerateRandomWithKeySize(rng, 1536);

  ///////////////////////////////////////
  // Generated Parameters
  Integer n = params.GetModulus();
  Integer p = params.GetPrime1();
  Integer q = params.GetPrime2();
  Integer d = params.GetPrivateExponent();
  Integer e = params.GetPublicExponent();

  ///////////////////////////////////////
  // Dump
  cout << "RSA Parameters:" << endl;
  cout << " n: " << n << endl;
  cout << " p: " << p << endl;
  cout << " q: " << q << endl;
  cout << " d: " << d << endl;
  cout << " e: " << e << endl;
  cout << endl;

  ///////////////////////////////////////
  // Create Keys
  auto privateKey = new MyPrivKey(params);
  RSA::PublicKey publicKey(params);


  // Message
  string message = "Yoda said, Do or Do Not. There is no try.";

  // Signer object
  RSASS<PSS, SHA1>::Signer signer(*privateKey);
    delete privateKey;

  // Create signature space
  size_t length = signer.MaxSignatureLength();
  SecByteBlock signature(length);

  // Sign message
  length = signer.SignMessage(rng, (const byte*) message.c_str(),
      message.length(), signature);

  // Resize now we know the true size of the signature
  signature.resize(length);

  // Verifier object
  RSASS<PSS, SHA1>::Verifier verifier(publicKey);

  // Verify
  bool result = verifier.VerifyMessage((const byte*)message.c_str(),
      message.length(), signature, signature.size());

  // Result
  if(true == result) {
      cout << "Signature on message verified" << endl;
  } else {
      cout << "Message verification failed" << endl;
  }

  return 0;
}