okamoto_uchiyama.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 OKAMOTO_UCHIYAMA_HEADER_GUARD
#define OKAMOTO_UCHIYAMA_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 {
    struct OkamotoUchiyamaPublicKey {
    public:
        BigInteger n;
        BigInteger G;
        BigInteger H;
    };

    struct OkamotoUchiyamaPrivateKey {
    public:
        BigInteger p;
        BigInteger q;
        BigInteger gp;
        BigInteger t;
    };

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

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

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

    struct OkamotoUchiyamaRandomizer : public RandomizerBase {
        OkamotoUchiyamaRandomizer ();

        OkamotoUchiyamaRandomizer (const BigInteger &data);
    };

    class OkamotoUchiyama : public CryptoProvider<OkamotoUchiyamaPublicKey, OkamotoUchiyamaPrivateKey, OkamotoUchiyamaCiphertext, OkamotoUchiyamaRandomizer> {
    public:
        OkamotoUchiyama ();

        OkamotoUchiyama (const OkamotoUchiyamaPublicKey &publicKey);

        OkamotoUchiyama (const OkamotoUchiyamaPublicKey &publicKey, const OkamotoUchiyamaPrivateKey &privateKey);

        ~OkamotoUchiyama () {}

        /* 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 pSquared;

        BigInteger messageSpace;

        size_t messageSpaceSize;

        BigInteger g;

        BigInteger lgpInv;

        BigInteger L (const BigInteger &input) const;

        /* Base class methods */

        virtual void validateParameters () {}

        virtual void doPrecomputations ();

        /* /Base class methods */

        OkamotoUchiyama (const OkamotoUchiyama &);

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

#endif//OKAMOTO_UCHIYAMA_HEADER_GUARD