crypto_provider.hpp

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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_IMPLEMENTATION_GUARD
#define CRYPTO_PROVIDER_IMPLEMENTATION_GUARD

namespace SeComLib {
namespace Core {
    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::CryptoProvider (const unsigned int keyLength) :
        keyLength(keyLength), hasPrivateKey(true), precomputeSpeedupValues(false) {
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::CryptoProvider (const T_PublicKey &publicKey, const unsigned int keyLength) :
        publicKey(publicKey), keyLength(keyLength), hasPrivateKey(false), precomputeSpeedupValues(true) {
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::CryptoProvider (const T_PublicKey &publicKey, const T_PrivateKey &privateKey, const unsigned int keyLength) :
        publicKey(publicKey), privateKey(privateKey), keyLength(keyLength), hasPrivateKey(true), precomputeSpeedupValues(true) {
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    T_Ciphertext CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::EncryptInteger (const BigInteger &plaintext) const {
        return this->RandomizeCiphertext(this->EncryptIntegerNonrandom(plaintext));
    }

#ifdef ENABLE_CRYPTO_PROVIDER_HOMOMORPHIC_OPERATIONS

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    T_Ciphertext CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::HomomorphicAdd (const T_Ciphertext &lhs, const T_Ciphertext &rhs) const {
        return (lhs * rhs) % this->GetEncryptionModulus();
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    T_Ciphertext CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::GetHomomorphicInverse (const T_Ciphertext &input) const {
        return input.GetInverseModN(this->GetEncryptionModulus());
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    T_Ciphertext CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::HomomorphicSubtract (const T_Ciphertext &lhs, const T_Ciphertext &rhs) const {
        return (lhs * rhs.GetInverseModN(this->GetEncryptionModulus())) % this->GetEncryptionModulus();
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    T_Ciphertext CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::HomomorphicMultiply (const T_Ciphertext &lhs, const BigInteger &rhs) const {
        if (rhs == 0) {
            throw std::runtime_error("The plaintext term should not be 0.");
        }

        return lhs.GetPowModN(rhs, this->GetEncryptionModulus());
    }
#endif

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    const BigInteger &CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::GetEncryptionModulus () const {
        return *this->encryptionModulus;
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    const BigInteger &CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::GetPositiveNegativeBoundary () const {
        return this->positiveNegativeBoundary;
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    const T_PublicKey &CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::GetPublicKey () const {
        return this->publicKey;
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    const T_PrivateKey &CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::GetPrivateKey () const {
        return this->privateKey;
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    T_Ciphertext CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::GetEncryptedZero (const bool randomized) const {
        if (randomized) {
            return this->RandomizeCiphertext(this->encryptedZero);
        }
        else {
            return this->encryptedZero;
        }
    }

    template <typename T_PublicKey, typename T_PrivateKey, typename T_Ciphertext, typename T_Randomizer>
    T_Ciphertext CryptoProvider<T_PublicKey, T_PrivateKey, T_Ciphertext, T_Randomizer>::GetEncryptedOne (const bool randomized) const {
        if (randomized) {
            return this->RandomizeCiphertext(this->encryptedOne);
        }
        else {
            return this->encryptedOne;
        }

    }
}//namespace Core
}//namespace SeComLib

#endif//CRYPTO_PROVIDER_IMPLEMENTATION_GUARD