eccrypto.h

Go to the documentation of this file.

#ifndef CRYPTOPP_ECCRYPTO_H
#define CRYPTOPP_ECCRYPTO_H

/*! \file
*/

#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 "ecp.h"
#include "ec2n.h"

NAMESPACE_BEGIN(CryptoPP)

//! Elliptic Curve Parameters
/*! This class corresponds to the ASN.1 sequence of the same name
    in ANSI X9.62 (also SEC 1).
*/
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;

        DL_GroupParameters_EC() : m_compress(false), m_encodeAsOID(false) {}
        DL_GroupParameters_EC(const OID &oid)
                : m_compress(false), m_encodeAsOID(false) {Initialize(oid);}
        DL_GroupParameters_EC(const EllipticCurve &ec, const Point &G, const Integer &n, const Integer &k = Integer::Zero())
                : m_compress(false), m_encodeAsOID(false) {Initialize(ec, G, n, k);}
        DL_GroupParameters_EC(BufferedTransformation &bt)
                : m_compress(false), m_encodeAsOID(false) {BERDecode(bt);}

        void Initialize(const EllipticCurve &ec, const Point &G, const Integer &n, const Integer &k = Integer::Zero())
        {
                this->m_groupPrecomputation.SetCurve(ec);
                SetSubgroupGenerator(G);
                m_n = n;
                m_k = k;
        }
        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));
        }
        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, NULL))
                        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);}

#ifdef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY
        const Point& GetBasePoint() const {return GetSubgroupGenerator();}
        const Integer& GetBasePointOrder() const {return GetSubgroupOrder();}
        void LoadRecommendedParameters(const OID &oid) {Initialize(oid);}
#endif

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
        bool m_compress, m_encodeAsOID;
        mutable Integer m_k;            // cofactor
};

//! EC public key
template <class EC>
class DL_PublicKey_EC : public DL_PublicKeyImpl<DL_GroupParameters_EC<EC> >
{
public:
        typedef typename EC::Point Element;

        void Initialize(const DL_GroupParameters_EC<EC> &params, const Element &Q)
                {this->AccessGroupParameters() = params; SetPublicElement(Q);}
        void Initialize(const EC &ec, const Element &G, const Integer &n, const Element &Q)
                {this->AccessGroupParameters().Initialize(ec, G, n); SetPublicElement(Q);}

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

//! EC private key
template <class EC>
class DL_PrivateKey_EC : public DL_PrivateKeyImpl<DL_GroupParameters_EC<EC> >
{
public:
        typedef typename EC::Point Element;

        void Initialize(const DL_GroupParameters_EC<EC> &params, const Integer &x)
                {this->AccessGroupParameters() = params; this->SetPrivateExponent(x);}
        void Initialize(const EC &ec, const Element &G, const Integer &n, const Integer &x)
                {this->AccessGroupParameters().Initialize(ec, G, n); this->SetPrivateExponent(x);}
        void Initialize(RandomNumberGenerator &rng, const DL_GroupParameters_EC<EC> &params)
                {GenerateRandom(rng, params);}
        void Initialize(RandomNumberGenerator &rng, const EC &ec, const Element &G, const Integer &n)
                {GenerateRandom(rng, DL_GroupParameters_EC<EC>(ec, G, n));}

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

//! Elliptic Curve Diffie-Hellman, AKA <a href="http://www.weidai.com/scan-mirror/ka.html#ECDH">ECDH</a>
template <class EC, class COFACTOR_OPTION = CPP_TYPENAME DL_GroupParameters_EC<EC>::DefaultCofactorOption>
struct ECDH
{
        typedef DH_Domain<DL_GroupParameters_EC<EC>, COFACTOR_OPTION> Domain;
};

/// Elliptic Curve Menezes-Qu-Vanstone, AKA <a href="http://www.weidai.com/scan-mirror/ka.html#ECMQV">ECMQV</a>
template <class EC, class COFACTOR_OPTION = CPP_TYPENAME DL_GroupParameters_EC<EC>::DefaultCofactorOption>
struct ECMQV
{
        typedef MQV_Domain<DL_GroupParameters_EC<EC>, COFACTOR_OPTION> Domain;
};

//! EC keys
template <class EC>
struct DL_Keys_EC
{
        typedef DL_PublicKey_EC<EC> PublicKey;
        typedef DL_PrivateKey_EC<EC> PrivateKey;
};

template <class EC, class H = SHA>
struct ECDSA;

//! ECDSA keys
template <class EC>
struct DL_Keys_ECDSA
{
        typedef DL_PublicKey_EC<EC> PublicKey;
        typedef DL_PrivateKey_WithSignaturePairwiseConsistencyTest<DL_PrivateKey_EC<EC>, ECDSA<EC> > PrivateKey;
};

//! ECDSA algorithm
template <class EC>
class DL_Algorithm_ECDSA : public DL_Algorithm_GDSA<typename EC::Point>
{
public:
        static const char * CRYPTOPP_API StaticAlgorithmName() {return "ECDSA";}
};

//! ECNR algorithm
template <class EC>
class DL_Algorithm_ECNR : public DL_Algorithm_NR<typename EC::Point>
{
public:
        static const char * CRYPTOPP_API StaticAlgorithmName() {return "ECNR";}
};

//! <a href="http://www.weidai.com/scan-mirror/sig.html#ECDSA">ECDSA</a>
template <class EC, class H>
struct ECDSA : public DL_SS<DL_Keys_ECDSA<EC>, DL_Algorithm_ECDSA<EC>, DL_SignatureMessageEncodingMethod_DSA, H>
{
};

//! ECNR
template <class EC, class H = SHA>
struct ECNR : public DL_SS<DL_Keys_EC<EC>, DL_Algorithm_ECNR<EC>, DL_SignatureMessageEncodingMethod_NR, H>
{
};

//! Elliptic Curve Integrated Encryption Scheme, AKA <a href="http://www.weidai.com/scan-mirror/ca.html#ECIES">ECIES</a>
/*! Default to (NoCofactorMultiplication and DHAES_MODE = false) for compatibilty with SEC1 and Crypto++ 4.2.
        The combination of (IncompatibleCofactorMultiplication and DHAES_MODE = true) is recommended for best
        efficiency and security. */
template <class EC, class COFACTOR_OPTION = NoCofactorMultiplication, bool DHAES_MODE = 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<SHA1> >,
                DL_EncryptionAlgorithm_Xor<HMAC<SHA1>, DHAES_MODE>,
                ECIES<EC> >
{
        static std::string CRYPTOPP_API StaticAlgorithmName() {return "ECIES";} // TODO: fix this after name is standardized
};

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_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_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> >;
CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKey_WithSignaturePairwiseConsistencyTest<DL_PrivateKey_EC<EC2N>, ECDSA<EC2N> >;

NAMESPACE_END

#endif

---