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1 files changed, 141 insertions, 0 deletions

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+#ifndef CRYPTOPP_MQV_H
+#define CRYPTOPP_MQV_H
+
+/** \file
+*/
+
+#include "gfpcrypt.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+//! .
+template <class GROUP_PARAMETERS, class COFACTOR_OPTION = CPP_TYPENAME GROUP_PARAMETERS::DefaultCofactorOption>
+class MQV_Domain : public AuthenticatedKeyAgreementDomain
+{
+public:
+	typedef GROUP_PARAMETERS GroupParameters;
+	typedef typename GroupParameters::Element Element;
+	typedef MQV_Domain<GROUP_PARAMETERS, COFACTOR_OPTION> Domain;
+
+	MQV_Domain() {}
+
+	MQV_Domain(const GroupParameters &params)
+		: m_groupParameters(params) {}
+
+	MQV_Domain(BufferedTransformation &bt)
+		{m_groupParameters.BERDecode(bt);}
+
+	template <class T1, class T2>
+	MQV_Domain(T1 v1, T2 v2)
+		{m_groupParameters.Initialize(v1, v2);}
+	
+	template <class T1, class T2, class T3>
+	MQV_Domain(T1 v1, T2 v2, T2 v3)
+		{m_groupParameters.Initialize(v1, v2, v3);}
+	
+	template <class T1, class T2, class T3, class T4>
+	MQV_Domain(T1 v1, T2 v2, T3 v3, T4 v4)
+		{m_groupParameters.Initialize(v1, v2, v3, v4);}
+
+	const GroupParameters & GetGroupParameters() const {return m_groupParameters;}
+	GroupParameters & AccessGroupParameters() {return m_groupParameters;}
+
+	CryptoParameters & AccessCryptoParameters() {return AccessAbstractGroupParameters();}
+
+	unsigned int AgreedValueLength() const {return GetAbstractGroupParameters().GetEncodedElementSize(false);}
+	unsigned int StaticPrivateKeyLength() const {return GetAbstractGroupParameters().GetSubgroupOrder().ByteCount();}
+	unsigned int StaticPublicKeyLength() const {return GetAbstractGroupParameters().GetEncodedElementSize(true);}
+
+	void GenerateStaticPrivateKey(RandomNumberGenerator &rng, byte *privateKey) const
+	{
+		Integer x(rng, Integer::One(), GetAbstractGroupParameters().GetMaxExponent());
+		x.Encode(privateKey, StaticPrivateKeyLength());
+	}
+
+	void GenerateStaticPublicKey(RandomNumberGenerator &rng, const byte *privateKey, byte *publicKey) const
+	{
+		const DL_GroupParameters<Element> &params = GetAbstractGroupParameters();
+		Integer x(privateKey, StaticPrivateKeyLength());
+		Element y = params.ExponentiateBase(x);
+		params.EncodeElement(true, y, publicKey);
+	}
+
+	unsigned int EphemeralPrivateKeyLength() const {return StaticPrivateKeyLength() + StaticPublicKeyLength();}
+	unsigned int EphemeralPublicKeyLength() const {return StaticPublicKeyLength();}
+
+	void GenerateEphemeralPrivateKey(RandomNumberGenerator &rng, byte *privateKey) const
+	{
+		const DL_GroupParameters<Element> &params = GetAbstractGroupParameters();
+		Integer x(rng, Integer::One(), params.GetMaxExponent());
+		x.Encode(privateKey, StaticPrivateKeyLength());
+		Element y = params.ExponentiateBase(x);
+		params.EncodeElement(true, y, privateKey+StaticPrivateKeyLength());
+	}
+
+	void GenerateEphemeralPublicKey(RandomNumberGenerator &rng, const byte *privateKey, byte *publicKey) const
+	{
+		memcpy(publicKey, privateKey+StaticPrivateKeyLength(), EphemeralPublicKeyLength());
+	}
+
+	bool Agree(byte *agreedValue,
+		const byte *staticPrivateKey, const byte *ephemeralPrivateKey, 
+		const byte *staticOtherPublicKey, const byte *ephemeralOtherPublicKey,
+		bool validateStaticOtherPublicKey=true) const
+	{
+		try
+		{
+			const DL_GroupParameters<Element> &params = GetAbstractGroupParameters();
+			Element WW = params.DecodeElement(staticOtherPublicKey, validateStaticOtherPublicKey);
+			Element VV = params.DecodeElement(ephemeralOtherPublicKey, true);
+
+			Integer s(staticPrivateKey, StaticPrivateKeyLength());
+			Integer u(ephemeralPrivateKey, StaticPrivateKeyLength());
+			Element V = params.DecodeElement(ephemeralPrivateKey+StaticPrivateKeyLength(), false);
+
+			const Integer &r = params.GetSubgroupOrder();
+			Integer h2 = Integer::Power2((r.BitCount()+1)/2);
+			Integer e = ((h2+params.ConvertElementToInteger(V)%h2)*s+u) % r;
+			Integer tt = h2 + params.ConvertElementToInteger(VV) % h2;
+
+			if (COFACTOR_OPTION::ToEnum() == NO_COFACTOR_MULTIPLICTION)
+			{
+				Element P = params.ExponentiateElement(WW, tt);
+				P = m_groupParameters.MultiplyElements(P, VV);
+				Element R[2];
+				const Integer e2[2] = {r, e};
+				params.SimultaneousExponentiate(R, P, e2, 2);
+				if (!params.IsIdentity(R[0]) || params.IsIdentity(R[1]))
+					return false;
+				params.EncodeElement(false, R[1], agreedValue);
+			}
+			else
+			{
+				const Integer &k = params.GetCofactor();
+				if (COFACTOR_OPTION::ToEnum() == COMPATIBLE_COFACTOR_MULTIPLICTION)
+					e = ModularArithmetic(r).Divide(e, k);
+				Element P = m_groupParameters.CascadeExponentiate(VV, k*e, WW, k*(e*tt%r));
+				if (params.IsIdentity(P))
+					return false;
+				params.EncodeElement(false, P, agreedValue);
+			}
+		}
+		catch (DL_BadElement &)
+		{
+			return false;
+		}
+		return true;
+	}
+
+private:
+	DL_GroupParameters<Element> & AccessAbstractGroupParameters() {return m_groupParameters;}
+	const DL_GroupParameters<Element> & GetAbstractGroupParameters() const {return m_groupParameters;}
+
+	GroupParameters m_groupParameters;
+};
+
+//! Menezes-Qu-Vanstone in GF(p) with key validation, AKA <a href="http://www.weidai.com/scan-mirror/ka.html#MQV">MQV</a>
+typedef MQV_Domain<DL_GroupParameters_GFP_DefaultSafePrime> MQV;
+
+NAMESPACE_END
+
+#endif