dh.h

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// dh.h - originally 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)
 
/// \brief Diffie-Hellman domain
/// \tparam GROUP_PARAMETERS group parameters
/// \tparam COFACTOR_OPTION 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.
/// \details For COFACTOR_OPTION, see CofactorMultiplicationOption.
/// \sa DL_SimpleKeyAgreementDomainBase
/// \since Crypto++ 1.0
template <class GROUP_PARAMETERS, class COFACTOR_OPTION = 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;
 
    virtual ~DH_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 Create 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 Create 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 Create 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();}
 
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>;
 
/// \brief Diffie-Hellman in GF(p)
/// \details DH() class is a typedef of DH_Domain(). The documentation that follows
///   does not exist. Rather the documentation was created in response to <a href="https://github.com/weidai11/cryptopp/issues/328">Issue
///   328, Diffie-Hellman example code not compiling</a>.
/// \details Generally speaking, a DH() object is ephemeral and is intended to execute one instance of the Diffie-Hellman protocol. The
///   private and public key parts are not intended to be set or persisted. Rather, a new set of domain parameters are generated each
///   time an object is created.
/// \details Once a DH() object is created, once can retrieve the ephemeral public key for the other party with code similar to the
///   following.
/// <pre>   AutoSeededRandomPool prng;
///   Integer p, q, g;
///   PrimeAndGenerator pg;
///
///   pg.Generate(1, prng, 512, 511);
///   p = pg.Prime();
///   q = pg.SubPrime();
///   g = pg.Generator();
///
///   DH dh(p, q, g);
///   SecByteBlock t1(dh.PrivateKeyLength()), t2(dh.PublicKeyLength());
///   dh.GenerateKeyPair(prng, t1, t2);
///   Integer k1(t1, t1.size()), k2(t2, t2.size());
///
///   cout << "Private key:\n";
///   cout << hex << k1 << endl;
///
///   cout << "Public key:\n";
///   cout << hex << k2 << endl;</pre>
///
/// \details Output of the program above will be similar to the following.
/// <pre>   $ ./cryptest.exe
///   Private key:
///   72b45a42371545e9d4880f48589aefh
///   Public key:
///   45fdb13f97b1840626f0250cec1dba4a23b894100b51fb5d2dd13693d789948f8bfc88f9200014b2
///   ba8dd8a6debc471c69ef1e2326c61184a2eca88ec866346bh</pre>
/// \sa <a href="http://www.cryptopp.com/wiki/Diffie-Hellman">Diffie-Hellman on the Crypto++ wiki</a> and
///   <a href="http://www.weidai.com/scan-mirror/ka.html#DH">Diffie-Hellman</a> in GF(p) with key validation
/// \since Crypto++ 1.0
#if defined(CRYPTOPP_DOXYGEN_PROCESSING)
struct DH : public DH_Domain<DL_GroupParameters_GFP_DefaultSafePrime>
{
    typedef DH_Domain<DL_GroupParameters_GFP_DefaultSafePrime> GroupParameters;
    typedef GroupParameters::Element Element;
 
    virtual ~DH() {}
 
    /// \brief Create an uninitialized Diffie-Hellman object
    DH() : DH_Domain() {}
 
    /// \brief Initialize a Diffie-Hellman object
    /// \param bt BufferedTransformation with group parameters and options
    DH(BufferedTransformation &bt) : DH_Domain(bt) {}
 
    /// \brief Initialize a Diffie-Hellman object
    /// \param params group parameters and options
    DH(const GroupParameters &params) : DH_Domain(params) {}
 
    /// \brief Create a Diffie-Hellman object
    /// \param rng a RandomNumberGenerator derived class
    /// \param modulusBits the size of the modulus, in bits
    /// \details This function overload of Initialize() creates a new Diffie-Hellman object because it
    ///   takes a RandomNumberGenerator() as a parameter.
    DH(RandomNumberGenerator &rng, unsigned int modulusBits) : DH_Domain(rng, modulusBits) {}
 
    /// \brief Initialize a Diffie-Hellman object
    /// \param p the modulus
    /// \param g the generator
    DH(const Integer &p, const Integer &g) : DH_Domain(p, g) {}
 
    /// \brief Initialize a Diffie-Hellman object
    /// \param p the modulus
    /// \param q the subgroup order
    /// \param g the generator
    DH(const Integer &p, const Integer &q, const Integer &g) : DH_Domain(p, q, g) {}
 
    /// \brief Creates a Diffie-Hellman object
    /// \param rng a RandomNumberGenerator derived class
    /// \param modulusBits the size of the modulus, in bits
    /// \details This function overload of Initialize() creates a new Diffie-Hellman object because it
    ///   takes a RandomNumberGenerator() as a parameter.
    void Initialize(RandomNumberGenerator &rng, unsigned int modulusBits)
        {AccessGroupParameters().Initialize(rng, modulusBits);}
 
    /// \brief Initialize a Diffie-Hellman object
    /// \param p the modulus
    /// \param g the generator
    void Initialize(const Integer &p, const Integer &g)
        {AccessGroupParameters().Initialize(p, g);}
 
    /// \brief Initialize a Diffie-Hellman object
    /// \param p the modulus
    /// \param q the subgroup order
    /// \param g the generator
    void Initialize(const Integer &p, const Integer &q, const Integer &g)
        {AccessGroupParameters().Initialize(p, q, g);}
};
#else
// The real DH class is a typedef.
typedef DH_Domain<DL_GroupParameters_GFP_DefaultSafePrime> DH;
#endif
 
NAMESPACE_END
 
#endif