eccrypto.h

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// eccrypto.h - originally written and placed in the public domain by Wei Dai
//              deterministic signatures added by by Douglas Roark

/// \file eccrypto.h
/// \brief Classes and functions for Elliptic Curves over prime and binary fields

#ifndef CRYPTOPP_ECCRYPTO_H
#define CRYPTOPP_ECCRYPTO_H

#include "config.h"
#include "cryptlib.h"
#include "pubkey.h"
#include "integer.h"
#include "asn.h"
#include "hmac.h"
#include "sha.h"
#include "gfpcrypt.h"
#include "dh.h"
#include "mqv.h"
#include "hmqv.h"
#include "fhmqv.h"
#include "ecp.h"
#include "ec2n.h"

#if CRYPTOPP_MSC_VERSION
# pragma warning(push)
# pragma warning(disable: 4231 4275)
#endif

NAMESPACE_BEGIN(CryptoPP)

/// \brief Elliptic Curve Parameters
/// \tparam EC elliptic curve field
/// \details This class corresponds to the ASN.1 sequence of the same name
///   in ANSI X9.62 and SEC 1. EC is currently defined for ECP and EC2N.
template <class EC>
class DL_GroupParameters_EC : public DL_GroupParametersImpl<EcPrecomputation<EC> >
{
    typedef DL_GroupParameters_EC<EC> ThisClass;

public:
    typedef EC EllipticCurve;
    typedef typename EllipticCurve::Point Point;
    typedef Point Element;
    typedef IncompatibleCofactorMultiplication DefaultCofactorOption;

    virtual ~DL_GroupParameters_EC() {}

    /// \brief Construct an EC GroupParameters
    DL_GroupParameters_EC() : m_compress(false), m_encodeAsOID(true) {}

    /// \brief Construct an EC GroupParameters
    /// \param oid the OID of a curve
    DL_GroupParameters_EC(const OID &oid)
        : m_compress(false), m_encodeAsOID(true) {Initialize(oid);}

    /// \brief Construct an EC GroupParameters
    /// \param ec the elliptic curve
    /// \param G the base point
    /// \param n the order of the base point
    /// \param k the cofactor
    DL_GroupParameters_EC(const EllipticCurve &ec, const Point &G, const Integer &n, const Integer &k = Integer::Zero())
        : m_compress(false), m_encodeAsOID(true) {Initialize(ec, G, n, k);}

    /// \brief Construct an EC GroupParameters
    /// \param bt BufferedTransformation with group parameters
    DL_GroupParameters_EC(BufferedTransformation &bt)
        : m_compress(false), m_encodeAsOID(true) {BERDecode(bt);}

    /// \brief Initialize an EC GroupParameters using {EC,G,n,k}
    /// \param ec the elliptic curve
    /// \param G the base point
    /// \param n the order of the base point
    /// \param k the cofactor
    /// \details This Initialize() function overload initializes group parameters from existing parameters.
    void Initialize(const EllipticCurve &ec, const Point &G, const Integer &n, const Integer &k = Integer::Zero())
    {
        this->m_groupPrecomputation.SetCurve(ec);
        this->SetSubgroupGenerator(G);
        m_n = n;
        m_k = k;
    }

    /// \brief Initialize a DL_GroupParameters_EC {EC,G,n,k}
    /// \param oid the OID of a curve
    /// \details This Initialize() function overload initializes group parameters from existing parameters.
    void Initialize(const OID &oid);

    // NameValuePairs
    bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const;
    void AssignFrom(const NameValuePairs &source);

    // GeneratibleCryptoMaterial interface
    /// this implementation doesn't actually generate a curve, it just initializes the parameters with existing values
    /*! parameters: (Curve, SubgroupGenerator, SubgroupOrder, Cofactor (optional)), or (GroupOID) */
    void GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg);

    // DL_GroupParameters
    const DL_FixedBasePrecomputation<Element> & GetBasePrecomputation() const {return this->m_gpc;}
    DL_FixedBasePrecomputation<Element> & AccessBasePrecomputation() {return this->m_gpc;}
    const Integer & GetSubgroupOrder() const {return m_n;}
    Integer GetCofactor() const;
    bool ValidateGroup(RandomNumberGenerator &rng, unsigned int level) const;
    bool ValidateElement(unsigned int level, const Element &element, const DL_FixedBasePrecomputation<Element> *precomp) const;
    bool FastSubgroupCheckAvailable() const {return false;}
    void EncodeElement(bool reversible, const Element &element, byte *encoded) const
    {
        if (reversible)
            GetCurve().EncodePoint(encoded, element, m_compress);
        else
            element.x.Encode(encoded, GetEncodedElementSize(false));
    }
    virtual unsigned int GetEncodedElementSize(bool reversible) const
    {
        if (reversible)
            return GetCurve().EncodedPointSize(m_compress);
        else
            return GetCurve().GetField().MaxElementByteLength();
    }
    Element DecodeElement(const byte *encoded, bool checkForGroupMembership) const
    {
        Point result;
        if (!GetCurve().DecodePoint(result, encoded, GetEncodedElementSize(true)))
            throw DL_BadElement();
        if (checkForGroupMembership && !ValidateElement(1, result, NULLPTR))
            throw DL_BadElement();
        return result;
    }
    Integer ConvertElementToInteger(const Element &element) const;
    Integer GetMaxExponent() const {return GetSubgroupOrder()-1;}
    bool IsIdentity(const Element &element) const {return element.identity;}
    void SimultaneousExponentiate(Element *results, const Element &base, const Integer *exponents, unsigned int exponentsCount) const;
    static std::string CRYPTOPP_API StaticAlgorithmNamePrefix() {return "EC";}

    // ASN1Key
    OID GetAlgorithmID() const;

    // used by MQV
    Element MultiplyElements(const Element &a, const Element &b) const;
    Element CascadeExponentiate(const Element &element1, const Integer &exponent1, const Element &element2, const Integer &exponent2) const;

    // non-inherited

    // enumerate OIDs for recommended parameters, use OID() to get first one
    static OID CRYPTOPP_API GetNextRecommendedParametersOID(const OID &oid);

    void BERDecode(BufferedTransformation &bt);
    void DEREncode(BufferedTransformation &bt) const;

    void SetPointCompression(bool compress) {m_compress = compress;}
    bool GetPointCompression() const {return m_compress;}

    void SetEncodeAsOID(bool encodeAsOID) {m_encodeAsOID = encodeAsOID;}
    bool GetEncodeAsOID() const {return m_encodeAsOID;}

    const EllipticCurve& GetCurve() const {return this->m_groupPrecomputation.GetCurve();}

    bool operator==(const ThisClass &rhs) const
        {return this->m_groupPrecomputation.GetCurve() == rhs.m_groupPrecomputation.GetCurve() && this->m_gpc.GetBase(this->m_groupPrecomputation) == rhs.m_gpc.GetBase(rhs.m_groupPrecomputation);}

protected:
    unsigned int FieldElementLength() const {return GetCurve().GetField().MaxElementByteLength();}
    unsigned int ExponentLength() const {return m_n.ByteCount();}

    OID m_oid;          // set if parameters loaded from a recommended curve
    Integer m_n;        // order of base point
    mutable Integer m_k;        // cofactor
    mutable bool m_compress, m_encodeAsOID;     // presentation details
};

/// \brief Elliptic Curve Discrete Log (DL) public key
/// \tparam EC elliptic curve field
template <class EC>
class DL_PublicKey_EC : public DL_PublicKeyImpl<DL_GroupParameters_EC<EC> >
{
public:
    typedef typename EC::Point Element;

    virtual ~DL_PublicKey_EC() {}

    /// \brief Initialize an EC Public Key using {GP,Q}
    /// \param params group parameters
    /// \param Q the public point
    /// \details This Initialize() function overload initializes a public key from existing parameters.
    void Initialize(const DL_GroupParameters_EC<EC> &params, const Element &Q)
        {this->AccessGroupParameters() = params; this->SetPublicElement(Q);}

    /// \brief Initialize an EC Public Key using {EC,G,n,Q}
    /// \param ec the elliptic curve
    /// \param G the base point
    /// \param n the order of the base point
    /// \param Q the public point
    /// \details This Initialize() function overload initializes a public key from existing parameters.
    void Initialize(const EC &ec, const Element &G, const Integer &n, const Element &Q)
        {this->AccessGroupParameters().Initialize(ec, G, n); this->SetPublicElement(Q);}

    // X509PublicKey
    void BERDecodePublicKey(BufferedTransformation &bt, bool parametersPresent, size_t size);
    void DEREncodePublicKey(BufferedTransformation &bt) const;
};

/// \brief Elliptic Curve Discrete Log (DL) private key
/// \tparam EC elliptic curve field
template <class EC>
class DL_PrivateKey_EC : public DL_PrivateKeyImpl<DL_GroupParameters_EC<EC> >
{
public:
    typedef typename EC::Point Element;

    virtual ~DL_PrivateKey_EC();

    /// \brief Initialize an EC Private Key using {GP,x}
    /// \param params group parameters
    /// \param x the private exponent
    /// \details This Initialize() function overload initializes a private key from existing parameters.
    void Initialize(const DL_GroupParameters_EC<EC> &params, const Integer &x)
        {this->AccessGroupParameters() = params; this->SetPrivateExponent(x);}

    /// \brief Initialize an EC Private Key using {EC,G,n,x}
    /// \param ec the elliptic curve
    /// \param G the base point
    /// \param n the order of the base point
    /// \param x the private exponent
    /// \details This Initialize() function overload initializes a private key from existing parameters.
    void Initialize(const EC &ec, const Element &G, const Integer &n, const Integer &x)
        {this->AccessGroupParameters().Initialize(ec, G, n); this->SetPrivateExponent(x);}

    /// \brief Create an EC private key
    /// \param rng a RandomNumberGenerator derived class
    /// \param params the EC group parameters
    /// \details This function overload of Initialize() creates a new private key because it
    ///   takes a RandomNumberGenerator() as a parameter. If you have an existing keypair,
    ///   then use one of the other Initialize() overloads.
    void Initialize(RandomNumberGenerator &rng, const DL_GroupParameters_EC<EC> &params)
        {this->GenerateRandom(rng, params);}

    /// \brief Create an EC private key
    /// \param rng a RandomNumberGenerator derived class
    /// \param ec the elliptic curve
    /// \param G the base point
    /// \param n the order of the base point
    /// \details This function overload of Initialize() creates a new private key because it
    ///   takes a RandomNumberGenerator() as a parameter. If you have an existing keypair,
    ///   then use one of the other Initialize() overloads.
    void Initialize(RandomNumberGenerator &rng, const EC &ec, const Element &G, const Integer &n)
        {this->GenerateRandom(rng, DL_GroupParameters_EC<EC>(ec, G, n));}

    // PKCS8PrivateKey
    void BERDecodePrivateKey(BufferedTransformation &bt, bool parametersPresent, size_t size);
    void DEREncodePrivateKey(BufferedTransformation &bt) const;
};

// Out-of-line dtor due to AIX and GCC, http://github.com/weidai11/cryptopp/issues/499
template<class EC>
DL_PrivateKey_EC<EC>::~DL_PrivateKey_EC() {}

/// \brief Elliptic Curve Diffie-Hellman
/// \tparam EC elliptic curve field
/// \tparam COFACTOR_OPTION cofactor multiplication option
/// \sa CofactorMultiplicationOption, <a href="http://www.weidai.com/scan-mirror/ka.html#ECDH">Elliptic Curve Diffie-Hellman, AKA ECDH</a>
/// \since Crypto++ 3.0
template <class EC, class COFACTOR_OPTION = typename DL_GroupParameters_EC<EC>::DefaultCofactorOption>
struct ECDH
{
    typedef DH_Domain<DL_GroupParameters_EC<EC>, COFACTOR_OPTION> Domain;
};

/// \brief Elliptic Curve Menezes-Qu-Vanstone
/// \tparam EC elliptic curve field
/// \tparam COFACTOR_OPTION cofactor multiplication option
/// \sa CofactorMultiplicationOption, <a href="http://www.weidai.com/scan-mirror/ka.html#ECMQV">Elliptic Curve Menezes-Qu-Vanstone, AKA ECMQV</a>
template <class EC, class COFACTOR_OPTION = typename DL_GroupParameters_EC<EC>::DefaultCofactorOption>
struct ECMQV
{
    typedef MQV_Domain<DL_GroupParameters_EC<EC>, COFACTOR_OPTION> Domain;
};

/// \brief Hashed Elliptic Curve Menezes-Qu-Vanstone
/// \tparam EC elliptic curve field
/// \tparam COFACTOR_OPTION cofactor multiplication option
/// \details This implementation follows Hugo Krawczyk's <a href="http://eprint.iacr.org/2005/176">HMQV: A High-Performance
///   Secure Diffie-Hellman Protocol</a>. Note: this implements HMQV only. HMQV-C with Key Confirmation is not provided.
/// \sa CofactorMultiplicationOption
template <class EC, class COFACTOR_OPTION = typename DL_GroupParameters_EC<EC>::DefaultCofactorOption, class HASH = SHA256>
struct ECHMQV
{
    typedef HMQV_Domain<DL_GroupParameters_EC<EC>, COFACTOR_OPTION, HASH> Domain;
};

typedef ECHMQV< ECP, DL_GroupParameters_EC< ECP >::DefaultCofactorOption,   SHA1 >::Domain ECHMQV160;
typedef ECHMQV< ECP, DL_GroupParameters_EC< ECP >::DefaultCofactorOption, SHA256 >::Domain ECHMQV256;
typedef ECHMQV< ECP, DL_GroupParameters_EC< ECP >::DefaultCofactorOption, SHA384 >::Domain ECHMQV384;
typedef ECHMQV< ECP, DL_GroupParameters_EC< ECP >::DefaultCofactorOption, SHA512 >::Domain ECHMQV512;

/// \brief Fully Hashed Elliptic Curve Menezes-Qu-Vanstone
/// \tparam EC elliptic curve field
/// \tparam COFACTOR_OPTION cofactor multiplication option
/// \details This implementation follows Augustin P. Sarr and Philippe Elbaz–Vincent, and Jean–Claude Bajard's
///   <a href="http://eprint.iacr.org/2009/408">A Secure and Efficient Authenticated Diffie-Hellman Protocol</a>.
///   Note: this is FHMQV, Protocol 5, from page 11; and not FHMQV-C.
/// \sa CofactorMultiplicationOption
template <class EC, class COFACTOR_OPTION = typename DL_GroupParameters_EC<EC>::DefaultCofactorOption, class HASH = SHA256>
struct ECFHMQV
{
    typedef FHMQV_Domain<DL_GroupParameters_EC<EC>, COFACTOR_OPTION, HASH> Domain;
};

typedef ECFHMQV< ECP, DL_GroupParameters_EC< ECP >::DefaultCofactorOption,   SHA1 >::Domain ECFHMQV160;
typedef ECFHMQV< ECP, DL_GroupParameters_EC< ECP >::DefaultCofactorOption, SHA256 >::Domain ECFHMQV256;
typedef ECFHMQV< ECP, DL_GroupParameters_EC< ECP >::DefaultCofactorOption, SHA384 >::Domain ECFHMQV384;
typedef ECFHMQV< ECP, DL_GroupParameters_EC< ECP >::DefaultCofactorOption, SHA512 >::Domain ECFHMQV512;

/// \brief Elliptic Curve Discrete Log (DL) keys
/// \tparam EC elliptic curve field
template <class EC>
struct DL_Keys_EC
{
    typedef DL_PublicKey_EC<EC> PublicKey;
    typedef DL_PrivateKey_EC<EC> PrivateKey;
};

// Forward declaration; documented below
template <class EC, class H>
struct ECDSA;

/// \brief Elliptic Curve DSA keys
/// \tparam EC elliptic curve field
/// \since Crypto++ 3.2
template <class EC>
struct DL_Keys_ECDSA
{
    typedef DL_PublicKey_EC<EC> PublicKey;
    typedef DL_PrivateKey_WithSignaturePairwiseConsistencyTest<DL_PrivateKey_EC<EC>, ECDSA<EC, SHA256> > PrivateKey;
};

/// \brief Elliptic Curve DSA (ECDSA) signature algorithm
/// \tparam EC elliptic curve field
/// \since Crypto++ 3.2
template <class EC>
class DL_Algorithm_ECDSA : public DL_Algorithm_GDSA<typename EC::Point>
{
public:
  CRYPTOPP_STATIC_CONSTEXPR const char* CRYPTOPP_API StaticAlgorithmName() {return "ECDSA";}
};

/// \brief Elliptic Curve DSA (ECDSA) signature algorithm based on RFC 6979
/// \tparam EC elliptic curve field
/// \sa <a href="http://tools.ietf.org/rfc/rfc6979.txt">RFC 6979, Deterministic Usage of the
///   Digital Signature Algorithm (DSA) and Elliptic Curve Digital Signature Algorithm (ECDSA)</a>
/// \since Crypto++ 6.0
template <class EC, class H>
class DL_Algorithm_ECDSA_RFC6979 : public DL_Algorithm_DSA_RFC6979<typename EC::Point, H>
{
public:
  CRYPTOPP_STATIC_CONSTEXPR const char* CRYPTOPP_API StaticAlgorithmName() {return "ECDSA-RFC6979";}
};

/// \brief Elliptic Curve NR (ECNR) signature algorithm
/// \tparam EC elliptic curve field
template <class EC>
class DL_Algorithm_ECNR : public DL_Algorithm_NR<typename EC::Point>
{
public:
  CRYPTOPP_STATIC_CONSTEXPR const char* CRYPTOPP_API StaticAlgorithmName() {return "ECNR";}
};

/// \brief Elliptic Curve DSA (ECDSA) signature scheme
/// \tparam EC elliptic curve field
/// \tparam H HashTransformation derived class
/// \sa <a href="http://www.weidai.com/scan-mirror/sig.html#ECDSA">ECDSA</a>
/// \since Crypto++ 3.2
template <class EC, class H>
struct ECDSA : public DL_SS<DL_Keys_ECDSA<EC>, DL_Algorithm_ECDSA<EC>, DL_SignatureMessageEncodingMethod_DSA, H>
{
};

/// \brief Elliptic Curve DSA (ECDSA) deterministic signature scheme
/// \tparam EC elliptic curve field
/// \tparam H HashTransformation derived class
/// \sa <a href="http://tools.ietf.org/rfc/rfc6979.txt">Deterministic Usage of the
///   Digital Signature Algorithm (DSA) and Elliptic Curve Digital Signature Algorithm (ECDSA)</a>
/// \since Crypto++ 6.0
template <class EC, class H>
struct ECDSA_RFC6979 : public DL_SS<
    DL_Keys_ECDSA<EC>,
    DL_Algorithm_ECDSA_RFC6979<EC, H>,
    DL_SignatureMessageEncodingMethod_DSA,
    H,
    ECDSA_RFC6979<EC,H> >
{
    static std::string CRYPTOPP_API StaticAlgorithmName() {return std::string("ECDSA-RFC6979/") + H::StaticAlgorithmName();}
};

/// \brief Elliptic Curve NR (ECNR) signature scheme
/// \tparam EC elliptic curve field
/// \tparam H HashTransformation derived class
template <class EC, class H = SHA1>
struct ECNR : public DL_SS<DL_Keys_EC<EC>, DL_Algorithm_ECNR<EC>, DL_SignatureMessageEncodingMethod_NR, H>
{
};

// ******************************************

template <class EC>
class DL_PublicKey_ECGDSA;
template <class EC>
class DL_PrivateKey_ECGDSA;

/// \brief Elliptic Curve German DSA key for ISO/IEC 15946
/// \tparam EC elliptic curve field
/// \sa ECGDSA
/// \since Crypto++ 6.0
template <class EC>
class DL_PrivateKey_ECGDSA : public DL_PrivateKeyImpl<DL_GroupParameters_EC<EC> >
{
public:
    typedef typename EC::Point Element;

    virtual ~DL_PrivateKey_ECGDSA() {}

    /// \brief Initialize an EC Private Key using {GP,x}
    /// \param params group parameters
    /// \param x the private exponent
    /// \details This Initialize() function overload initializes a private key from existing parameters.
    void Initialize(const DL_GroupParameters_EC<EC> &params, const Integer &x)
    {
        this->AccessGroupParameters() = params;
        this->SetPrivateExponent(x);
        CRYPTOPP_ASSERT(x>=1 && x<=params.GetSubgroupOrder()-1);
    }

    /// \brief Initialize an EC Private Key using {EC,G,n,x}
    /// \param ec the elliptic curve
    /// \param G the base point
    /// \param n the order of the base point
    /// \param x the private exponent
    /// \details This Initialize() function overload initializes a private key from existing parameters.
    void Initialize(const EC &ec, const Element &G, const Integer &n, const Integer &x)
    {
        this->AccessGroupParameters().Initialize(ec, G, n);
        this->SetPrivateExponent(x);
        CRYPTOPP_ASSERT(x>=1 && x<=this->AccessGroupParameters().GetSubgroupOrder()-1);
    }

    /// \brief Create an EC private key
    /// \param rng a RandomNumberGenerator derived class
    /// \param params the EC group parameters
    /// \details This function overload of Initialize() creates a new private key because it
    ///   takes a RandomNumberGenerator() as a parameter. If you have an existing keypair,
    ///   then use one of the other Initialize() overloads.
    void Initialize(RandomNumberGenerator &rng, const DL_GroupParameters_EC<EC> &params)
        {this->GenerateRandom(rng, params);}

    /// \brief Create an EC private key
    /// \param rng a RandomNumberGenerator derived class
    /// \param ec the elliptic curve
    /// \param G the base point
    /// \param n the order of the base point
    /// \details This function overload of Initialize() creates a new private key because it
    ///   takes a RandomNumberGenerator() as a parameter. If you have an existing keypair,
    ///   then use one of the other Initialize() overloads.
    void Initialize(RandomNumberGenerator &rng, const EC &ec, const Element &G, const Integer &n)
        {this->GenerateRandom(rng, DL_GroupParameters_EC<EC>(ec, G, n));}

    virtual void MakePublicKey(DL_PublicKey_ECGDSA<EC> &pub) const
    {
        const DL_GroupParameters<Element>& params = this->GetAbstractGroupParameters();
        pub.AccessAbstractGroupParameters().AssignFrom(params);
        const Integer &xInv = this->GetPrivateExponent().InverseMod(params.GetSubgroupOrder());
        pub.SetPublicElement(params.ExponentiateBase(xInv));
        CRYPTOPP_ASSERT(xInv.NotZero());
    }

    virtual bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
    {
        return GetValueHelper<DL_PrivateKey_ECGDSA<EC>,
            DL_PrivateKey_ECGDSA<EC> >(this, name, valueType, pValue).Assignable();
    }

    virtual void AssignFrom(const NameValuePairs &source)
    {
        AssignFromHelper<DL_PrivateKey_ECGDSA<EC>,
            DL_PrivateKey_ECGDSA<EC> >(this, source);
    }

    // PKCS8PrivateKey
    void BERDecodePrivateKey(BufferedTransformation &bt, bool parametersPresent, size_t size);
    void DEREncodePrivateKey(BufferedTransformation &bt) const;
};

/// \brief Elliptic Curve German DSA key for ISO/IEC 15946
/// \tparam EC elliptic curve field
/// \sa ECGDSA
/// \since Crypto++ 6.0
template <class EC>
class DL_PublicKey_ECGDSA : public DL_PublicKeyImpl<DL_GroupParameters_EC<EC> >
{
    typedef DL_PublicKey_ECGDSA<EC> ThisClass;

public:
    typedef typename EC::Point Element;

    virtual ~DL_PublicKey_ECGDSA() {}

    /// \brief Initialize an EC Public Key using {GP,Q}
    /// \param params group parameters
    /// \param Q the public point
    /// \details This Initialize() function overload initializes a public key from existing parameters.
    void Initialize(const DL_GroupParameters_EC<EC> &params, const Element &Q)
        {this->AccessGroupParameters() = params; this->SetPublicElement(Q);}

    /// \brief Initialize an EC Public Key using {EC,G,n,Q}
    /// \param ec the elliptic curve
    /// \param G the base point
    /// \param n the order of the base point
    /// \param Q the public point
    /// \details This Initialize() function overload initializes a public key from existing parameters.
    void Initialize(const EC &ec, const Element &G, const Integer &n, const Element &Q)
        {this->AccessGroupParameters().Initialize(ec, G, n); this->SetPublicElement(Q);}

    virtual void AssignFrom(const NameValuePairs &source)
    {
        DL_PrivateKey_ECGDSA<EC> *pPrivateKey = NULLPTR;
        if (source.GetThisPointer(pPrivateKey))
            pPrivateKey->MakePublicKey(*this);
        else
        {
            this->AccessAbstractGroupParameters().AssignFrom(source);
            AssignFromHelper(this, source)
                CRYPTOPP_SET_FUNCTION_ENTRY(PublicElement);
        }
    }

    // DL_PublicKey<T>
    virtual void SetPublicElement(const Element &y)
        {this->AccessPublicPrecomputation().SetBase(this->GetAbstractGroupParameters().GetGroupPrecomputation(), y);}

    // X509PublicKey
    void BERDecodePublicKey(BufferedTransformation &bt, bool parametersPresent, size_t size);
    void DEREncodePublicKey(BufferedTransformation &bt) const;
};

/// \brief Elliptic Curve German DSA keys for ISO/IEC 15946
/// \tparam EC elliptic curve field
/// \sa ECGDSA
/// \since Crypto++ 6.0
template <class EC>
struct DL_Keys_ECGDSA
{
    typedef DL_PublicKey_ECGDSA<EC> PublicKey;
    typedef DL_PrivateKey_ECGDSA<EC> PrivateKey;
};

/// \brief Elliptic Curve German DSA signature algorithm
/// \tparam EC elliptic curve field
/// \sa ECGDSA
/// \since Crypto++ 6.0
template <class EC>
class DL_Algorithm_ECGDSA : public DL_Algorithm_GDSA_ISO15946<typename EC::Point>
{
public:
  CRYPTOPP_STATIC_CONSTEXPR const char* CRYPTOPP_API StaticAlgorithmName() {return "ECGDSA";}
};

/// \brief Elliptic Curve German Digital Signature Algorithm signature scheme
/// \tparam EC elliptic curve field
/// \tparam H HashTransformation derived class
/// \sa Erwin Hess, Marcus Schafheutle, and Pascale Serf <A
///   HREF="http://www.teletrust.de/fileadmin/files/oid/ecgdsa_final.pdf">The Digital Signature Scheme
///   ECGDSA (October 24, 2006)</A>
/// \since Crypto++ 6.0
template <class EC, class H>
struct ECGDSA : public DL_SS<
    DL_Keys_ECGDSA<EC>,
    DL_Algorithm_ECGDSA<EC>,
    DL_SignatureMessageEncodingMethod_DSA,
    H>
{
    static std::string CRYPTOPP_API StaticAlgorithmName() {return std::string("ECGDSA-ISO15946/") + H::StaticAlgorithmName();}
};

// ******************************************

/// \brief Elliptic Curve Integrated Encryption Scheme
/// \tparam COFACTOR_OPTION cofactor multiplication option
/// \tparam HASH HashTransformation derived class used for key drivation and MAC computation
/// \tparam DHAES_MODE flag indicating if the MAC includes additional context parameters such as <em>u·V</em>, <em>v·U</em> and label
/// \tparam LABEL_OCTETS flag indicating if the label size is specified in octets or bits
/// \details ECIES is an Elliptic Curve based Integrated Encryption Scheme (IES). The scheme combines a Key Encapsulation
///   Method (KEM) with a Data Encapsulation Method (DEM) and a MAC tag. The scheme is
///   <A HREF="http://en.wikipedia.org/wiki/ciphertext_indistinguishability">IND-CCA2</A>, which is a strong notion of security.
///   You should prefer an Integrated Encryption Scheme over homegrown schemes.
/// \details The library's original implementation is based on an early P1363 draft, which itself appears to be based on an early Certicom
///   SEC-1 draft (or an early SEC-1 draft was based on a P1363 draft). Crypto++ 4.2 used the early draft in its Integrated Ecryption
///   Schemes with <tt>NoCofactorMultiplication</tt>, <tt>DHAES_MODE=false</tt> and <tt>LABEL_OCTETS=true</tt>.
/// \details If you desire an Integrated Encryption Scheme with Crypto++ 4.2 compatibility, then use the ECIES template class with
///   <tt>NoCofactorMultiplication</tt>, <tt>DHAES_MODE=false</tt> and <tt>LABEL_OCTETS=true</tt>.
/// \details If you desire an Integrated Encryption Scheme with Bouncy Castle 1.54 and Botan 1.11 compatibility, then use the ECIES
///   template class with <tt>NoCofactorMultiplication</tt>, <tt>DHAES_MODE=true</tt> and <tt>LABEL_OCTETS=false</tt>.
/// \details The default template parameters ensure compatibility with Bouncy Castle 1.54 and Botan 1.11. The combination of
///   <tt>IncompatibleCofactorMultiplication</tt> and <tt>DHAES_MODE=true</tt> is recommended for best efficiency and security.
///   SHA1 is used for compatibility reasons, but it can be changed if desired. SHA-256 or another hash will likely improve the
///   security provided by the MAC. The hash is also used in the key derivation function as a PRF.
/// \details Below is an example of constructing a Crypto++ 4.2 compatible ECIES encryptor and decryptor.
/// <pre>
///     AutoSeededRandomPool prng;
///     DL_PrivateKey_EC<ECP> key;
///     key.Initialize(prng, ASN1::secp160r1());
///
///     ECIES<ECP,SHA1,NoCofactorMultiplication,true,true>::Decryptor decryptor(key);
///     ECIES<ECP,SHA1,NoCofactorMultiplication,true,true>::Encryptor encryptor(decryptor);
/// </pre>
/// \sa DLIES, <a href="http://www.weidai.com/scan-mirror/ca.html#ECIES">Elliptic Curve Integrated Encryption Scheme (ECIES)</a>,
///   Martínez, Encinas, and Ávila's <A HREF="http://digital.csic.es/bitstream/10261/32671/1/V2-I2-P7-13.pdf">A Survey of the Elliptic
///   Curve Integrated Encryption Schemes</A>
/// \since Crypto++ 4.0, Crypto++ 5.7 for Bouncy Castle and Botan compatibility
template <class EC, class HASH = SHA1, class COFACTOR_OPTION = NoCofactorMultiplication, bool DHAES_MODE = true, bool LABEL_OCTETS = false>
struct ECIES
    : public DL_ES<
        DL_Keys_EC<EC>,
        DL_KeyAgreementAlgorithm_DH<typename EC::Point, COFACTOR_OPTION>,
        DL_KeyDerivationAlgorithm_P1363<typename EC::Point, DHAES_MODE, P1363_KDF2<HASH> >,
        DL_EncryptionAlgorithm_Xor<HMAC<HASH>, DHAES_MODE, LABEL_OCTETS>,
        ECIES<EC> >
{
    // TODO: fix this after name is standardized
    CRYPTOPP_STATIC_CONSTEXPR const char* CRYPTOPP_API StaticAlgorithmName() {return "ECIES";}
};

NAMESPACE_END

#ifdef CRYPTOPP_MANUALLY_INSTANTIATE_TEMPLATES
#include "eccrypto.cpp"
#endif

NAMESPACE_BEGIN(CryptoPP)

CRYPTOPP_DLL_TEMPLATE_CLASS DL_GroupParameters_EC<ECP>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_GroupParameters_EC<EC2N>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PublicKeyImpl<DL_GroupParameters_EC<ECP> >;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PublicKeyImpl<DL_GroupParameters_EC<EC2N> >;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PublicKey_EC<ECP>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PublicKey_EC<EC2N>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PublicKey_ECGDSA<ECP>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PublicKey_ECGDSA<EC2N>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKeyImpl<DL_GroupParameters_EC<ECP> >;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKeyImpl<DL_GroupParameters_EC<EC2N> >;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKey_EC<ECP>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKey_EC<EC2N>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKey_ECGDSA<ECP>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKey_ECGDSA<EC2N>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_Algorithm_GDSA<ECP::Point>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_Algorithm_GDSA<EC2N::Point>;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKey_WithSignaturePairwiseConsistencyTest<DL_PrivateKey_EC<ECP>, ECDSA<ECP, SHA256> >;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKey_WithSignaturePairwiseConsistencyTest<DL_PrivateKey_EC<EC2N>, ECDSA<EC2N, SHA256> >;

NAMESPACE_END

#if CRYPTOPP_MSC_VERSION
# pragma warning(pop)
#endif

#endif