paillier.h

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/*
SeComLib
Copyright 2012-2013 TU Delft, Information Security & Privacy Lab (http://isplab.tudelft.nl/)

Contributors:
Inald Lagendijk (R.L.Lagendijk@TUDelft.nl)
Mihai Todor (todormihai@gmail.com)
Thijs Veugen (P.J.M.Veugen@tudelft.nl)
Zekeriya Erkin (z.erkin@tudelft.nl)

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
#ifndef PAILLIER_HEADER_GUARD
#define PAILLIER_HEADER_GUARD

#include "big_integer.h"
#include "random_provider.h"
#include "ciphertext_base.h"
#include "crypto_provider.h"
#include "utils/config.h"

//include C++ headers
#include <stdexcept>

namespace SeComLib {
namespace Core {
    //uncomment this to use the standard version of the Paillier key generation and encryption algorithms
    //#define USE_STANDARD_PAILLIER_ALGORITHM

    struct PaillierPublicKey {
    public:
        BigInteger n;
        BigInteger g;
    };

    struct PaillierPrivateKey {
    public:
        BigInteger p;//required if decrypting using CRT
        BigInteger q;//required if decrypting using CRT
    #ifdef USE_STANDARD_PAILLIER_ALGORITHM
        BigInteger lambda;
        BigInteger mu;
    #endif
    };

    class PaillierCiphertext : public CiphertextBase<PaillierCiphertext> {
    public:
        PaillierCiphertext ();

        PaillierCiphertext (const std::shared_ptr<BigInteger> &encryptionModulus);

        PaillierCiphertext (const BigInteger &data, const std::shared_ptr<BigInteger> &encryptionModulus);
    };

    struct PaillierRandomizer : public RandomizerBase {
        PaillierRandomizer ();

        PaillierRandomizer (const BigInteger &data);
    };

    class Paillier : public CryptoProvider<PaillierPublicKey, PaillierPrivateKey, PaillierCiphertext, PaillierRandomizer> {
    public:
        Paillier ();

        Paillier (const PaillierPublicKey &publicKey);

        Paillier (const PaillierPublicKey &publicKey, const PaillierPrivateKey &privateKey);

        ~Paillier () {}

        /* Base class methods */

        virtual bool GenerateKeys ();

        virtual BigInteger DecryptInteger (const Ciphertext &ciphertext) const;

        virtual Ciphertext EncryptIntegerNonrandom (const BigInteger &plaintext) const;

        virtual Randomizer GetRandomizer () const;

        virtual Ciphertext RandomizeCiphertext (const Ciphertext &ciphertext) const;

        virtual const BigInteger &GetMessageSpaceUpperBound () const;

        virtual size_t GetMessageSpaceSize () const;

        /* /Base class methods */

    private:
        BigInteger pMinusOne;

        BigInteger qMinusOne;

        BigInteger nMinusOne;

        BigInteger pSquared;

        BigInteger qSquared;

        BigInteger nSquared;

        BigInteger pTimesPInvModQ;

        BigInteger qTimesQInvModP;

        BigInteger hp;

        BigInteger hq;

        BigInteger L (const BigInteger &input, const BigInteger &d) const;

        /* Base class methods */

        virtual void validateParameters () {}

        virtual void doPrecomputations ();

        /* /Base class methods */

        Paillier (const Paillier &);

        Paillier operator= (const Paillier &);
    };
}//namespace Core
}//namespace SeComLib

#endif//PAILLIER_HEADER_GUARD