data_packing/service_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 SERVICE_PROVIDER_HEADER_GUARD
#define SERVICE_PROVIDER_HEADER_GUARD

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

#include "secure_comparison_server.h"


//include C++ libraries
#include <string>
#include <deque>
#include <stdexcept>

namespace SeComLib {
using namespace Core;
using namespace PrivateRecommendationsUtils;

//hackish way of computing everything for only a single user (see also client.h)
#define FIRST_USER_ONLY

namespace PrivateRecommendationsDataPacking {
    //forward-declare required classes
    class PrivacyServiceProvider;

    class ServiceProvider {
    public:
        typedef std::deque<Paillier::Ciphertext> EncryptedUserData;

        typedef std::deque<EncryptedUserData> EncryptedUserDataContainer;

        typedef std::deque<Paillier::Ciphertext> PackedData;

        typedef std::deque<PackedData> PackedItems;

        typedef std::deque<PackedItems> PackedItemContainer;

        ServiceProvider (const PaillierPublicKey &paillierPublicKey, const DgkPublicKey &dgkPublicKey);

        ~ServiceProvider () {}

        void GenerateDummyDatabase (const EncryptedUserDataContainer &normalizedScaledRatings);

        void ComputeSimilarityValues (const EncryptedUserDataContainer &normalizedScaledRatings);

        void ComputeUserRecommendations (const PackedItems &sparseRatings);

        const Paillier::Ciphertext &GetEncryptedL (const size_t userId) const;

        const PackedData &GetEncryptedURSum (const size_t userId) const;

    #if 0
        const PackedData ComputeURSum (const size_t userId, const PackedData &userPackedSparseRatings) const;
    #endif

        void SetPrivacyServiceProvider (const std::shared_ptr<const PrivacyServiceProvider> &privacyServiceProvider);

        size_t GetBucketSize () const;

        size_t GetMaxPackedBuckets () const;

        const std::shared_ptr<SecureComparisonServer> &GetSecureComparisonServer () const;

        const std::shared_ptr<SecureMultiplicationServer<Paillier>> &GetSecureMultiplicationServer () const;

    private:
        std::weak_ptr<const PrivacyServiceProvider> privacyServiceProvider;

        Paillier paillierCryptoProvider;

        Dgk dgkCryptoProvider;

        size_t userCount;

        size_t itemCount;

        size_t denselyRatedItemCount;

        size_t scaledNormalizedRatingBitSize;

        unsigned int digitsToPreserve;

        size_t kappa;

        BigInteger similarityTreshold;

        size_t bucketSize;

        size_t maxPackedBuckets;

        std::deque<BigInteger> emptyBuckets;

        PackedItemContainer packedNormalizedScaledRatings;

        EncryptedUserDataContainer gamma;

        EncryptedUserData LValues;

        PackedItems URSumContainer;

        std::shared_ptr<SecureComparisonServer> secureComparisonServer;

        std::shared_ptr<SecureMultiplicationServer<Paillier>> secureMultiplicationServer;

        static const std::string configurationPath;

        ServiceProvider (ServiceProvider const &);

        ServiceProvider operator= (ServiceProvider const &);
    };
}//namespace PrivateRecommendationsDataPacking
}//namespace SeComLib

#endif//SERVICE_PROVIDER_HEADER_GUARD