crypto_provider.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 CRYPTO_PROVIDER_HEADER_GUARD
#define CRYPTO_PROVIDER_HEADER_GUARD

#include "big_integer.h"
#include "ciphertext_base.h"
#include "randomizer_cache_parameters.h"
#include "randomizer_container.h"
#include "randomizer_base.h"
#include "randomizer_cache.h"

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

namespace SeComLib {
namespace Core {
    //uncomment this to enable homomorphic operations on ciphertexts via crypto providers
    //#define ENABLE_CRYPTO_PROVIDER_HOMOMORPHIC_OPERATIONS

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    class CryptoProvider {
    public:
        typedef T_Ciphertext Ciphertext;

        typedef T_Randomizer Randomizer;

        CryptoProvider (const unsigned int keyLength);

        CryptoProvider (const T_PublicKey &publicKey, const unsigned int keyLength);

        CryptoProvider (const T_PublicKey &publicKey, const T_PrivateKey &privateKey, const unsigned int keyLength);

        virtual ~CryptoProvider () {}

        virtual bool GenerateKeys () = 0;

        virtual T_Ciphertext EncryptInteger (const BigInteger &plaintext) const;

        virtual BigInteger DecryptInteger (const T_Ciphertext &ciphertext) const = 0;

        virtual T_Ciphertext EncryptIntegerNonrandom (const BigInteger &plaintext) const = 0;

        virtual T_Randomizer GetRandomizer () const = 0;

        virtual T_Ciphertext RandomizeCiphertext (const T_Ciphertext &ciphertext) const = 0;
        
    #ifdef ENABLE_CRYPTO_PROVIDER_HOMOMORPHIC_OPERATIONS
        T_Ciphertext HomomorphicAdd (const T_Ciphertext &lhs, const T_Ciphertext &rhs) const;

        T_Ciphertext GetHomomorphicInverse (const T_Ciphertext &input) const;

        T_Ciphertext HomomorphicSubtract (const T_Ciphertext &lhs, const T_Ciphertext &rhs) const;

        T_Ciphertext HomomorphicMultiply (const T_Ciphertext &lhs, const BigInteger &rhs) const;
    #endif

        const BigInteger &GetEncryptionModulus () const;

        virtual const BigInteger &GetMessageSpaceUpperBound () const = 0;

        virtual const BigInteger &GetPositiveNegativeBoundary () const;

        virtual size_t GetMessageSpaceSize () const = 0;

        const T_PublicKey &GetPublicKey () const;

        const T_PrivateKey &GetPrivateKey () const;

        Ciphertext GetEncryptedZero (const bool randomized = true) const;

        Ciphertext GetEncryptedOne (const bool randomized = true) const;
        
    protected:
        typedef RandomizerCache<RandomizerContainer<CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>, RandomizerCacheParameters>> RandomizerCacheType;

        std::unique_ptr<RandomizerCacheType> randomizerCache;

        T_PublicKey publicKey;

        T_PrivateKey privateKey;

        unsigned int keyLength;

        std::shared_ptr<BigInteger> encryptionModulus;

        BigInteger positiveNegativeBoundary;

        bool hasPrivateKey;

        bool precomputeSpeedupValues;

        T_Ciphertext encryptedZero;

        T_Ciphertext encryptedOne;

        virtual void validateParameters () = 0;

        virtual void doPrecomputations () = 0;

    private:
        //CryptoProvider (const CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext> &);//need C++11 delete to disable this

        //CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext> operator= (const CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext> &);//need C++11 delete to disable this
    };
}//namespace Core
}//namespace SeComLib

//Separate the implementation from the declaration
#include "crypto_provider.hpp"

#endif//CRYPTO_PROVIDER_HEADER_GUARD