source: git/src-cryptopp/dh.h

// dh.h - written and placed in the public domain by Wei Dai

//! \file dh.h
//! \brief Classes for Diffie-Hellman key exchange

#ifndef CRYPTOPP_DH_H
#define CRYPTOPP_DH_H

#include "cryptlib.h"
#include "gfpcrypt.h"
#include "algebra.h"

NAMESPACE_BEGIN(CryptoPP)

//! \class DH_Domain
//! \brief Diffie-Hellman domain
//! \tparam GROUP_PARAMETERS group parameters
//! \tparam COFACTOR_OPTION \ref CofactorMultiplicationOption "cofactor multiplication option"
//! \details A Diffie-Hellman domain is a set of parameters that must be shared
//!   by two parties in a key agreement protocol, along with the algorithms
//!   for generating key pairs and deriving agreed values.
template <class GROUP_PARAMETERS, class COFACTOR_OPTION = CPP_TYPENAME GROUP_PARAMETERS::DefaultCofactorOption>
class DH_Domain : public DL_SimpleKeyAgreementDomainBase<typename GROUP_PARAMETERS::Element>
{
        typedef DL_SimpleKeyAgreementDomainBase<typename GROUP_PARAMETERS::Element> Base;

public:
        typedef GROUP_PARAMETERS GroupParameters;
        typedef typename GroupParameters::Element Element;
        typedef DL_KeyAgreementAlgorithm_DH<Element, COFACTOR_OPTION> DH_Algorithm;
        typedef DH_Domain<GROUP_PARAMETERS, COFACTOR_OPTION> Domain;

        //! \brief Construct a Diffie-Hellman domain
        DH_Domain() {}

        //! \brief Construct a Diffie-Hellman domain
        //! \param params group parameters and options
        DH_Domain(const GroupParameters &params)
                : m_groupParameters(params) {}

        //! \brief Construct a Diffie-Hellman domain
        //! \param bt BufferedTransformation with group parameters and options
        DH_Domain(BufferedTransformation &bt)
                {m_groupParameters.BERDecode(bt);}

        //! \brief Construct a Diffie-Hellman domain
        //! \tparam T2 template parameter used as a constructor parameter
        //! \param v1 RandomNumberGenerator derived class
        //! \param v2 second parameter
        //! \details v1 and v2 are passed directly to the GROUP_PARAMETERS object.
        template <class T2>
        DH_Domain(RandomNumberGenerator &v1, const T2 &v2)
                {m_groupParameters.Initialize(v1, v2);}

        //! \brief Construct a Diffie-Hellman domain
        //! \tparam T2 template parameter used as a constructor parameter
        //! \tparam T3 template parameter used as a constructor parameter
        //! \param v1 RandomNumberGenerator derived class
        //! \param v2 second parameter
        //! \param v3 third parameter
        //! \details v1, v2 and v3 are passed directly to the GROUP_PARAMETERS object.
        template <class T2, class T3>
        DH_Domain(RandomNumberGenerator &v1, const T2 &v2, const T3 &v3)
                {m_groupParameters.Initialize(v1, v2, v3);}

        //! \brief Construct a Diffie-Hellman domain
        //! \tparam T2 template parameter used as a constructor parameter
        //! \tparam T3 template parameter used as a constructor parameter
        //! \tparam T4 template parameter used as a constructor parameter
        //! \param v1 RandomNumberGenerator derived class
        //! \param v2 second parameter
        //! \param v3 third parameter
        //! \param v4 fourth parameter
        //! \details v1, v2, v3 and v4 are passed directly to the GROUP_PARAMETERS object.
        template <class T2, class T3, class T4>
        DH_Domain(RandomNumberGenerator &v1, const T2 &v2, const T3 &v3, const T4 &v4)
                {m_groupParameters.Initialize(v1, v2, v3, v4);}

        //! \brief Construct a Diffie-Hellman domain
        //! \tparam T1 template parameter used as a constructor parameter
        //! \tparam T2 template parameter used as a constructor parameter
        //! \param v1 first parameter
        //! \param v2 second parameter
        //! \details v1 and v2 are passed directly to the GROUP_PARAMETERS object.
        template <class T1, class T2>
        DH_Domain(const T1 &v1, const T2 &v2)
                {m_groupParameters.Initialize(v1, v2);}

        //! \brief Construct a Diffie-Hellman domain
        //! \tparam T1 template parameter used as a constructor parameter
        //! \tparam T2 template parameter used as a constructor parameter
        //! \tparam T3 template parameter used as a constructor parameter
        //! \param v1 first parameter
        //! \param v2 second parameter
        //! \param v3 third parameter
        //! \details v1, v2 and v3 are passed directly to the GROUP_PARAMETERS object.
        template <class T1, class T2, class T3>
        DH_Domain(const T1 &v1, const T2 &v2, const T3 &v3)
                {m_groupParameters.Initialize(v1, v2, v3);}

        //! \brief Construct a Diffie-Hellman domain
        //! \tparam T1 template parameter used as a constructor parameter
        //! \tparam T2 template parameter used as a constructor parameter
        //! \tparam T3 template parameter used as a constructor parameter
        //! \tparam T4 template parameter used as a constructor parameter
        //! \param v1 first parameter
        //! \param v2 second parameter
        //! \param v3 third parameter
        //! \param v4 fourth parameter
        //! \details v1, v2, v3 and v4 are passed directly to the GROUP_PARAMETERS object.
        template <class T1, class T2, class T3, class T4>
        DH_Domain(const T1 &v1, const T2 &v2, const T3 &v3, const T4 &v4)
                {m_groupParameters.Initialize(v1, v2, v3, v4);}

        //! \brief Retrieves the group parameters for this domain
        //! \return the group parameters for this domain as a const reference
        const GroupParameters & GetGroupParameters() const {return m_groupParameters;}
        //! \brief Retrieves the group parameters for this domain
        //! \return the group parameters for this domain as a non-const reference
        GroupParameters & AccessGroupParameters() {return m_groupParameters;}

        //! \brief Generate a public key from a private key in this domain
        //! \param rng RandomNumberGenerator derived class
        //! \param privateKey byte buffer with the previously generated private key
        //! \param publicKey byte buffer for the generated public key in this domain
        //! \details If using a FIPS 140-2 validated library on Windows, then this class will perform
        //!   a self test to ensure the key pair is pairwise consistent. Non-FIPS and non-Windows
        //!   builds of the library do not provide FIPS validated cryptography, so the code should be
        //!   removed by the optimizer.
        //! \pre <tt>COUNTOF(publicKey) == PublicKeyLength()</tt>
        void GeneratePublicKey(RandomNumberGenerator &rng, const byte *privateKey, byte *publicKey) const
        {
                Base::GeneratePublicKey(rng, privateKey, publicKey);

                if (FIPS_140_2_ComplianceEnabled())
                {
                        SecByteBlock privateKey2(this->PrivateKeyLength());
                        this->GeneratePrivateKey(rng, privateKey2);

                        SecByteBlock publicKey2(this->PublicKeyLength());
                        Base::GeneratePublicKey(rng, privateKey2, publicKey2);

                        SecByteBlock agreedValue(this->AgreedValueLength()), agreedValue2(this->AgreedValueLength());
                        bool agreed1 = this->Agree(agreedValue, privateKey, publicKey2);
                        bool agreed2 = this->Agree(agreedValue2, privateKey2, publicKey);

                        if (!agreed1 || !agreed2 || agreedValue != agreedValue2)
                                throw SelfTestFailure(this->AlgorithmName() + ": pairwise consistency test failed");
                }
        }

        static std::string CRYPTOPP_API StaticAlgorithmName()
                {return GroupParameters::StaticAlgorithmNamePrefix() + DH_Algorithm::StaticAlgorithmName();}
        std::string AlgorithmName() const {return StaticAlgorithmName();}

#ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
        virtual ~DH_Domain() {}
#endif

private:
        const DL_KeyAgreementAlgorithm<Element> & GetKeyAgreementAlgorithm() const
                {return Singleton<DH_Algorithm>().Ref();}
        DL_GroupParameters<Element> & AccessAbstractGroupParameters()
                {return m_groupParameters;}

        GroupParameters m_groupParameters;
};

CRYPTOPP_DLL_TEMPLATE_CLASS DH_Domain<DL_GroupParameters_GFP_DefaultSafePrime>;

//! <a href="http://www.weidai.com/scan-mirror/ka.html#DH">Diffie-Hellman</a> in GF(p) with key validation
typedef DH_Domain<DL_GroupParameters_GFP_DefaultSafePrime> DH;

NAMESPACE_END

#endif