private_recommendations_utils/dgk_comparison_server.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 DGK_COMPARISON_SERVER_HEADER_GUARD
#define DGK_COMPARISON_SERVER_HEADER_GUARD

//include our headers
#include "utils/config.h"
#include "core/big_integer.h"
#include "core/random_provider.h"
#include "core/paillier.h"
#include "core/dgk.h"

namespace SeComLib {
using namespace Core;

namespace PrivateRecommendationsUtils {
    //forward-declare required classes
    class DgkComparisonClient;

    class DgkComparisonServer {
    public:
        DgkComparisonServer (const Paillier &paillierCryptoProvider, const Dgk &dgkCryptoProvider, const size_t l);

        ~DgkComparisonServer () {}

        Paillier::Ciphertext Compare (const BigInteger &rModTwoPowL) const;

        Paillier::Ciphertext ComputeDi (const BigInteger &rModTwoPowL) const;

        size_t GetMSBPosition () const;

        void SetClient (const std::shared_ptr<DgkComparisonClient> &dgkComparisonClient);

    private:
        const Paillier &paillierCryptoProvider;

        const Dgk &dgkCryptoProvider;

        std::weak_ptr<const DgkComparisonClient> dgkComparisonClient;

        size_t l;

        Dgk::Ciphertext computeTau (const BigInteger &a, const BigInteger &tSP) const;

        DgkComparisonServer (DgkComparisonServer const &);

        DgkComparisonServer operator= (DgkComparisonServer const &);
    };
}//namespace PrivateRecommendationsUtils
}//namespace SeComLib

#endif//DGK_COMPARISON_SERVER_HEADER_GUARD