text: #ifndef CRYPTOPP_GFPCRYPT_H
  #define CRYPTOPP_GFPCRYPT_H
  
  /** \file
  	Implementation of schemes based on DL over GF(p)
  */
  
  #include "config.h"
  
  #if CRYPTOPP_MSC_VERSION
  # pragma warning(push)
  # pragma warning(disable: 4189)
  #endif
  
  #include "cryptlib.h"
  #include "pubkey.h"
  #include "integer.h"
  #include "modexppc.h"
  #include "algparam.h"
  #include "smartptr.h"
  #include "sha.h"
  #include "asn.h"
  #include "hmac.h"
  #include "misc.h"
  
  NAMESPACE_BEGIN(CryptoPP)
  
  CRYPTOPP_DLL_TEMPLATE_CLASS DL_GroupParameters<Integer>;
  
  //! _
  class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE DL_GroupParameters_IntegerBased : public ASN1CryptoMaterial<DL_GroupParameters<Integer> >
  {
  	typedef DL_GroupParameters_IntegerBased ThisClass;
  
  public:
  	void Initialize(const DL_GroupParameters_IntegerBased &params)
  		{Initialize(params.GetModulus(), params.GetSubgroupOrder(), params.GetSubgroupGenerator());}
  	void Initialize(RandomNumberGenerator &rng, unsigned int pbits)
  		{GenerateRandom(rng, MakeParameters("ModulusSize", (int)pbits));}
  	void Initialize(const Integer &p, const Integer &g)
  		{SetModulusAndSubgroupGenerator(p, g); SetSubgroupOrder(ComputeGroupOrder(p)/2);}
  	void Initialize(const Integer &p, const Integer &q, const Integer &g)
  		{SetModulusAndSubgroupGenerator(p, g); SetSubgroupOrder(q);}
  
  	// ASN1Object interface
  	void BERDecode(BufferedTransformation &bt);
  	void DEREncode(BufferedTransformation &bt) const;
  
  	// GeneratibleCryptoMaterial interface
  	/*! parameters: (ModulusSize, SubgroupOrderSize (optional)) */
  	void GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg);
  	bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const;
  	void AssignFrom(const NameValuePairs &source);
  
  	// DL_GroupParameters
  	const Integer & GetSubgroupOrder() const {return m_q;}
  	Integer GetGroupOrder() const {return GetFieldType() == 1 ? GetModulus()-Integer::One() : GetModulus()+Integer::One();}
  	bool ValidateGroup(RandomNumberGenerator &rng, unsigned int level) const;
  	bool ValidateElement(unsigned int level, const Integer &element, const DL_FixedBasePrecomputation<Integer> *precomp) const;
  	bool FastSubgroupCheckAvailable() const {return GetCofactor() == 2;}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	// Cygwin i386 crash at -O3; see .
  	void EncodeElement(bool reversible, const Element &element, byte *encoded) const;
  	unsigned int GetEncodedElementSize(bool reversible) const;
  #else
  	void EncodeElement(bool reversible, const Element &element, byte *encoded) const
  		{CRYPTOPP_UNUSED(reversible); element.Encode(encoded, GetModulus().ByteCount());}
  	unsigned int GetEncodedElementSize(bool reversible) const
  		{CRYPTOPP_UNUSED(reversible); return GetModulus().ByteCount();}
  #endif
  
  	Integer DecodeElement(const byte *encoded, bool checkForGroupMembership) const;
  	Integer ConvertElementToInteger(const Element &element) const
  		{return element;}
  	Integer GetMaxExponent() const;
  	static std::string CRYPTOPP_API StaticAlgorithmNamePrefix() {return "";}
  
  	OID GetAlgorithmID() const;
  
  	virtual const Integer & GetModulus() const =0;
  	virtual void SetModulusAndSubgroupGenerator(const Integer &p, const Integer &g) =0;
  
  	void SetSubgroupOrder(const Integer &q)
  		{m_q = q; ParametersChanged();}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_GroupParameters_IntegerBased() {}
  #endif
  
  protected:
  	Integer ComputeGroupOrder(const Integer &modulus) const
  		{return modulus-(GetFieldType() == 1 ? 1 : -1);}
  
  	// GF(p) = 1, GF(p^2) = 2
  	virtual int GetFieldType() const =0;
  	virtual unsigned int GetDefaultSubgroupOrderSize(unsigned int modulusSize) const;
  
  private:
  	Integer m_q;
  };
  
  //! _
  template <class GROUP_PRECOMP, class BASE_PRECOMP = DL_FixedBasePrecomputationImpl<CPP_TYPENAME GROUP_PRECOMP::Element> >
  class CRYPTOPP_NO_VTABLE DL_GroupParameters_IntegerBasedImpl : public DL_GroupParametersImpl<GROUP_PRECOMP, BASE_PRECOMP, DL_GroupParameters_IntegerBased>
  {
  	typedef DL_GroupParameters_IntegerBasedImpl<GROUP_PRECOMP, BASE_PRECOMP> ThisClass;
  
  public:
  	typedef typename GROUP_PRECOMP::Element Element;
  
  	// GeneratibleCryptoMaterial interface
  	bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
  		{return GetValueHelper<DL_GroupParameters_IntegerBased>(this, name, valueType, pValue).Assignable();}
  
  	void AssignFrom(const NameValuePairs &source)
  		{AssignFromHelper<DL_GroupParameters_IntegerBased>(this, source);}
  
  	// DL_GroupParameters
  	const DL_FixedBasePrecomputation<Element> & GetBasePrecomputation() const {return this->m_gpc;}
  	DL_FixedBasePrecomputation<Element> & AccessBasePrecomputation() {return this->m_gpc;}
  
  	// IntegerGroupParameters
  	const Integer & GetModulus() const {return this->m_groupPrecomputation.GetModulus();}
      const Integer & GetGenerator() const {return this->m_gpc.GetBase(this->GetGroupPrecomputation());}
  
  	void SetModulusAndSubgroupGenerator(const Integer &p, const Integer &g)		// these have to be set together
  		{this->m_groupPrecomputation.SetModulus(p); this->m_gpc.SetBase(this->GetGroupPrecomputation(), g); this->ParametersChanged();}
  
  	// non-inherited
  	bool operator==(const DL_GroupParameters_IntegerBasedImpl<GROUP_PRECOMP, BASE_PRECOMP> &rhs) const
  		{return GetModulus() == rhs.GetModulus() && GetGenerator() == rhs.GetGenerator() && this->GetSubgroupOrder() == rhs.GetSubgroupOrder();}
  	bool operator!=(const DL_GroupParameters_IntegerBasedImpl<GROUP_PRECOMP, BASE_PRECOMP> &rhs) const
  		{return !operator==(rhs);}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_GroupParameters_IntegerBasedImpl() {}
  #endif
  };
  
  CRYPTOPP_DLL_TEMPLATE_CLASS DL_GroupParameters_IntegerBasedImpl<ModExpPrecomputation>;
  
  //! GF(p) group parameters
  class CRYPTOPP_DLL DL_GroupParameters_GFP : public DL_GroupParameters_IntegerBasedImpl<ModExpPrecomputation>
  {
  public:
  	// DL_GroupParameters
  	bool IsIdentity(const Integer &element) const {return element == Integer::One();}
  	void SimultaneousExponentiate(Element *results, const Element &base, const Integer *exponents, unsigned int exponentsCount) const;
  
  	// NameValuePairs interface
  	bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
  	{
  		return GetValueHelper<DL_GroupParameters_IntegerBased>(this, name, valueType, pValue).Assignable();
  	}
  
  	// 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;
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_GroupParameters_GFP() {}
  #endif
  
  protected:
  	int GetFieldType() const {return 1;}
  };
  
  //! GF(p) group parameters that default to same primes
  class CRYPTOPP_DLL DL_GroupParameters_GFP_DefaultSafePrime : public DL_GroupParameters_GFP
  {
  public:
  	typedef NoCofactorMultiplication DefaultCofactorOption;
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_GroupParameters_GFP_DefaultSafePrime() {}
  #endif
  
  protected:
  	unsigned int GetDefaultSubgroupOrderSize(unsigned int modulusSize) const {return modulusSize-1;}
  };
  
  //! GDSA algorithm
  template <class T>
  class DL_Algorithm_GDSA : public DL_ElgamalLikeSignatureAlgorithm<T>
  {
  public:
  	CRYPTOPP_CONSTEXPR static const char * CRYPTOPP_API StaticAlgorithmName() {return "DSA-1363";}
  
  	void Sign(const DL_GroupParameters<T> &params, const Integer &x, const Integer &k, const Integer &e, Integer &r, Integer &s) const
  	{
  		const Integer &q = params.GetSubgroupOrder();
  		r %= q;
  		Integer kInv = k.InverseMod(q);
  		s = (kInv * (x*r + e)) % q;
  		assert(!!r && !!s);
  	}
  
  	bool Verify(const DL_GroupParameters<T> &params, const DL_PublicKey<T> &publicKey, const Integer &e, const Integer &r, const Integer &s) const
  	{
  		const Integer &q = params.GetSubgroupOrder();
  		if (r>=q || r<1 || s>=q || s<1)
  			return false;
  
  		Integer w = s.InverseMod(q);
  		Integer u1 = (e * w) % q;
  		Integer u2 = (r * w) % q;
  		// verify r == (g^u1 * y^u2 mod p) mod q
  		return r == params.ConvertElementToInteger(publicKey.CascadeExponentiateBaseAndPublicElement(u1, u2)) % q;
  	}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_Algorithm_GDSA() {}
  #endif
  };
  
  CRYPTOPP_DLL_TEMPLATE_CLASS DL_Algorithm_GDSA<Integer>;
  
  //! NR algorithm
  template <class T>
  class DL_Algorithm_NR : public DL_ElgamalLikeSignatureAlgorithm<T>
  {
  public:
  	CRYPTOPP_CONSTEXPR static const char * CRYPTOPP_API StaticAlgorithmName() {return "NR";}
  
  	void Sign(const DL_GroupParameters<T> &params, const Integer &x, const Integer &k, const Integer &e, Integer &r, Integer &s) const
  	{
  		const Integer &q = params.GetSubgroupOrder();
  		r = (r + e) % q;
  		s = (k - x*r) % q;
  		assert(!!r);
  	}
  
  	bool Verify(const DL_GroupParameters<T> &params, const DL_PublicKey<T> &publicKey, const Integer &e, const Integer &r, const Integer &s) const
  	{
  		const Integer &q = params.GetSubgroupOrder();
  		if (r>=q || r<1 || s>=q)
  			return false;
  
  		// check r == (m_g^s * m_y^r + m) mod m_q
  		return r == (params.ConvertElementToInteger(publicKey.CascadeExponentiateBaseAndPublicElement(s, r)) + e) % q;
  	}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_Algorithm_NR() {}
  #endif
  };
  
  /*! DSA public key format is defined in 7.3.3 of RFC 2459. The
  	private key format is defined in 12.9 of PKCS #11 v2.10. */
  template <class GP>
  class DL_PublicKey_GFP : public DL_PublicKeyImpl<GP>
  {
  public:
  	void Initialize(const DL_GroupParameters_IntegerBased &params, const Integer &y)
  		{this->AccessGroupParameters().Initialize(params); this->SetPublicElement(y);}
  	void Initialize(const Integer &p, const Integer &g, const Integer &y)
  		{this->AccessGroupParameters().Initialize(p, g); this->SetPublicElement(y);}
  	void Initialize(const Integer &p, const Integer &q, const Integer &g, const Integer &y)
  		{this->AccessGroupParameters().Initialize(p, q, g); this->SetPublicElement(y);}
  
  	// X509PublicKey
  	void BERDecodePublicKey(BufferedTransformation &bt, bool, size_t)
  		{this->SetPublicElement(Integer(bt));}
  	void DEREncodePublicKey(BufferedTransformation &bt) const
  		{this->GetPublicElement().DEREncode(bt);}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_PublicKey_GFP() {}
  #endif
  };
  
  //! DL private key (in GF(p) groups)
  template <class GP>
  class DL_PrivateKey_GFP : public DL_PrivateKeyImpl<GP>
  {
  public:
  	void Initialize(RandomNumberGenerator &rng, unsigned int modulusBits)
  		{this->GenerateRandomWithKeySize(rng, modulusBits);}
  	void Initialize(RandomNumberGenerator &rng, const Integer &p, const Integer &g)
  		{this->GenerateRandom(rng, MakeParameters("Modulus", p)("SubgroupGenerator", g));}
  	void Initialize(RandomNumberGenerator &rng, const Integer &p, const Integer &q, const Integer &g)
  		{this->GenerateRandom(rng, MakeParameters("Modulus", p)("SubgroupOrder", q)("SubgroupGenerator", g));}
  	void Initialize(const DL_GroupParameters_IntegerBased &params, const Integer &x)
  		{this->AccessGroupParameters().Initialize(params); this->SetPrivateExponent(x);}
  	void Initialize(const Integer &p, const Integer &g, const Integer &x)
  		{this->AccessGroupParameters().Initialize(p, g); this->SetPrivateExponent(x);}
  	void Initialize(const Integer &p, const Integer &q, const Integer &g, const Integer &x)
  		{this->AccessGroupParameters().Initialize(p, q, g); this->SetPrivateExponent(x);}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_PrivateKey_GFP() {}
  #endif
  };
  
  //! DL signing/verification keys (in GF(p) groups)
  struct DL_SignatureKeys_GFP
  {
  	typedef DL_GroupParameters_GFP GroupParameters;
  	typedef DL_PublicKey_GFP<GroupParameters> PublicKey;
  	typedef DL_PrivateKey_GFP<GroupParameters> PrivateKey;
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_SignatureKeys_GFP() {}
  #endif
  };
  
  //! DL encryption/decryption keys (in GF(p) groups)
  struct DL_CryptoKeys_GFP
  {
  	typedef DL_GroupParameters_GFP_DefaultSafePrime GroupParameters;
  	typedef DL_PublicKey_GFP<GroupParameters> PublicKey;
  	typedef DL_PrivateKey_GFP<GroupParameters> PrivateKey;
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_CryptoKeys_GFP() {}
  #endif
  };
  
  //! provided for backwards compatibility, this class uses the old non-standard Crypto++ key format
  template <class BASE>
  class DL_PublicKey_GFP_OldFormat : public BASE
  {
  public:
  	void BERDecode(BufferedTransformation &bt)
  	{
  		BERSequenceDecoder seq(bt);
  			Integer v1(seq);
  			Integer v2(seq);
  			Integer v3(seq);
  
  			if (seq.EndReached())
  			{
  				this->AccessGroupParameters().Initialize(v1, v1/2, v2);
  				this->SetPublicElement(v3);
  			}
  			else
  			{
  				Integer v4(seq);
  				this->AccessGroupParameters().Initialize(v1, v2, v3);
  				this->SetPublicElement(v4);
  			}
  
  		seq.MessageEnd();
  	}
  
  	void DEREncode(BufferedTransformation &bt) const
  	{
  		DERSequenceEncoder seq(bt);
  			this->GetGroupParameters().GetModulus().DEREncode(seq);
  			if (this->GetGroupParameters().GetCofactor() != 2)
  				this->GetGroupParameters().GetSubgroupOrder().DEREncode(seq);
  			this->GetGroupParameters().GetGenerator().DEREncode(seq);
  			this->GetPublicElement().DEREncode(seq);
  		seq.MessageEnd();
  	}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_PublicKey_GFP_OldFormat() {}
  #endif
  };
  
  //! provided for backwards compatibility, this class uses the old non-standard Crypto++ key format
  template <class BASE>
  class DL_PrivateKey_GFP_OldFormat : public BASE
  {
  public:
  	void BERDecode(BufferedTransformation &bt)
  	{
  		BERSequenceDecoder seq(bt);
  			Integer v1(seq);
  			Integer v2(seq);
  			Integer v3(seq);
  			Integer v4(seq);
  
  			if (seq.EndReached())
  			{
  				this->AccessGroupParameters().Initialize(v1, v1/2, v2);
  				this->SetPrivateExponent(v4 % (v1/2));	// some old keys may have x >= q
  			}
  			else
  			{
  				Integer v5(seq);
  				this->AccessGroupParameters().Initialize(v1, v2, v3);
  				this->SetPrivateExponent(v5);
  			}
  
  		seq.MessageEnd();
  	}
  
  	void DEREncode(BufferedTransformation &bt) const
  	{
  		DERSequenceEncoder seq(bt);
  			this->GetGroupParameters().GetModulus().DEREncode(seq);
  			if (this->GetGroupParameters().GetCofactor() != 2)
  				this->GetGroupParameters().GetSubgroupOrder().DEREncode(seq);
  			this->GetGroupParameters().GetGenerator().DEREncode(seq);
  			this->GetGroupParameters().ExponentiateBase(this->GetPrivateExponent()).DEREncode(seq);
  			this->GetPrivateExponent().DEREncode(seq);
  		seq.MessageEnd();
  	}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_PrivateKey_GFP_OldFormat() {}
  #endif
  };
  
  //! <a href="http://www.weidai.com/scan-mirror/sig.html#DSA-1363">DSA-1363</a>
  template <class H>
  struct GDSA : public DL_SS<
  	DL_SignatureKeys_GFP,
  	DL_Algorithm_GDSA<Integer>,
  	DL_SignatureMessageEncodingMethod_DSA,
  	H>
  {
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~GDSA() {}
  #endif
  };
  
  //! <a href="http://www.weidai.com/scan-mirror/sig.html#NR">NR</a>
  template <class H>
  struct NR : public DL_SS<
  	DL_SignatureKeys_GFP,
  	DL_Algorithm_NR<Integer>,
  	DL_SignatureMessageEncodingMethod_NR,
  	H>
  {
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~NR() {}
  #endif
  };
  
  //! DSA group parameters, these are GF(p) group parameters that are allowed by the DSA standard
  class CRYPTOPP_DLL DL_GroupParameters_DSA : public DL_GroupParameters_GFP
  {
  public:
  	/*! also checks that the lengths of p and q are allowed by the DSA standard */
  	bool ValidateGroup(RandomNumberGenerator &rng, unsigned int level) const;
  	/*! parameters: (ModulusSize), or (Modulus, SubgroupOrder, SubgroupGenerator) */
  	/*! ModulusSize must be between DSA::MIN_PRIME_LENGTH and DSA::MAX_PRIME_LENGTH, and divisible by DSA::PRIME_LENGTH_MULTIPLE */
  	void GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg);
  
  	static bool CRYPTOPP_API IsValidPrimeLength(unsigned int pbits)
  		{return pbits >= MIN_PRIME_LENGTH && pbits <= MAX_PRIME_LENGTH && pbits % PRIME_LENGTH_MULTIPLE == 0;}
  
  	enum {MIN_PRIME_LENGTH = 1024, MAX_PRIME_LENGTH = 3072, PRIME_LENGTH_MULTIPLE = 1024};
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_GroupParameters_DSA() {}
  #endif
  };
  
  template <class H>
  class DSA2;
  
  //! DSA keys
  struct DL_Keys_DSA
  {
  	typedef DL_PublicKey_GFP<DL_GroupParameters_DSA> PublicKey;
  	typedef DL_PrivateKey_WithSignaturePairwiseConsistencyTest<DL_PrivateKey_GFP<DL_GroupParameters_DSA>, DSA2<SHA> > PrivateKey;
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_Keys_DSA() {}
  #endif
  };
  
  //! <a href="http://en.wikipedia.org/wiki/Digital_Signature_Algorithm">DSA</a>, as specified in FIPS 186-3
  // class named DSA2 instead of DSA for backwards compatibility (DSA was a non-template class)
  template <class H>
  class DSA2 : public DL_SS<
  	DL_Keys_DSA,
  	DL_Algorithm_GDSA<Integer>,
  	DL_SignatureMessageEncodingMethod_DSA,
  	H,
  	DSA2<H> >
  {
  public:
  	static std::string CRYPTOPP_API StaticAlgorithmName() {return "DSA/" + (std::string)H::StaticAlgorithmName();}
  
  #ifdef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY
  	enum {MIN_PRIME_LENGTH = 1024, MAX_PRIME_LENGTH = 3072, PRIME_LENGTH_MULTIPLE = 1024};
  #endif
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DSA2() {}
  #endif
  };
  
  //! DSA with SHA-1, typedef'd for backwards compatibility
  typedef DSA2<SHA> DSA;
  
  CRYPTOPP_DLL_TEMPLATE_CLASS DL_PublicKey_GFP<DL_GroupParameters_DSA>;
  CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKey_GFP<DL_GroupParameters_DSA>;
  CRYPTOPP_DLL_TEMPLATE_CLASS DL_PrivateKey_WithSignaturePairwiseConsistencyTest<DL_PrivateKey_GFP<DL_GroupParameters_DSA>, DSA2<SHA> >;
  
  //! the XOR encryption method, for use with DL-based cryptosystems
  template <class MAC, bool DHAES_MODE>
  class DL_EncryptionAlgorithm_Xor : public DL_SymmetricEncryptionAlgorithm
  {
  public:
  	bool ParameterSupported(const char *name) const {return strcmp(name, Name::EncodingParameters()) == 0;}
  	size_t GetSymmetricKeyLength(size_t plaintextLength) const
  		{return plaintextLength + MAC::DEFAULT_KEYLENGTH;}
  	size_t GetSymmetricCiphertextLength(size_t plaintextLength) const
  		{return plaintextLength + MAC::DIGESTSIZE;}
  	size_t GetMaxSymmetricPlaintextLength(size_t ciphertextLength) const
  		{return (unsigned int)SaturatingSubtract(ciphertextLength, (unsigned int)MAC::DIGESTSIZE);}
  	void SymmetricEncrypt(RandomNumberGenerator &rng, const byte *key, const byte *plaintext, size_t plaintextLength, byte *ciphertext, const NameValuePairs &parameters) const
  	{
  		CRYPTOPP_UNUSED(rng);
  		const byte *cipherKey = NULL, *macKey = NULL;
  		if (DHAES_MODE)
  		{
  			macKey = key;
  			cipherKey = key + MAC::DEFAULT_KEYLENGTH;
  		}
  		else
  		{
  			cipherKey = key;
  			macKey = key + plaintextLength;
  		}
  
  		ConstByteArrayParameter encodingParameters;
  		parameters.GetValue(Name::EncodingParameters(), encodingParameters);
  
  		if (plaintextLength)	// Coverity finding
  			xorbuf(ciphertext, plaintext, cipherKey, plaintextLength);
  
  		MAC mac(macKey);
  		mac.Update(ciphertext, plaintextLength);
  		mac.Update(encodingParameters.begin(), encodingParameters.size());
  		if (DHAES_MODE)
  		{
  			byte L[8] = {0,0,0,0};
  			PutWord(false, BIG_ENDIAN_ORDER, L+4, word32(encodingParameters.size()));
  			mac.Update(L, 8);
  		}
  		mac.Final(ciphertext + plaintextLength);
  	}
  	DecodingResult SymmetricDecrypt(const byte *key, const byte *ciphertext, size_t ciphertextLength, byte *plaintext, const NameValuePairs &parameters) const
  	{
  		size_t plaintextLength = GetMaxSymmetricPlaintextLength(ciphertextLength);
  		const byte *cipherKey, *macKey;
  		if (DHAES_MODE)
  		{
  			macKey = key;
  			cipherKey = key + MAC::DEFAULT_KEYLENGTH;
  		}
  		else
  		{
  			cipherKey = key;
  			macKey = key + plaintextLength;
  		}
  
  		ConstByteArrayParameter encodingParameters;
  		parameters.GetValue(Name::EncodingParameters(), encodingParameters);
  
  		MAC mac(macKey);
  		mac.Update(ciphertext, plaintextLength);
  		mac.Update(encodingParameters.begin(), encodingParameters.size());
  		if (DHAES_MODE)
  		{
  			byte L[8] = {0,0,0,0};
  			PutWord(false, BIG_ENDIAN_ORDER, L+4, word32(encodingParameters.size()));
  			mac.Update(L, 8);
  		}
  		if (!mac.Verify(ciphertext + plaintextLength))
  			return DecodingResult();
  
  		if (plaintextLength)	// Coverity finding
  			xorbuf(plaintext, ciphertext, cipherKey, plaintextLength);
  
  		return DecodingResult(plaintextLength);
  	}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_EncryptionAlgorithm_Xor() {}
  #endif
  };
  
  //! _
  template <class T, bool DHAES_MODE, class KDF>
  class DL_KeyDerivationAlgorithm_P1363 : public DL_KeyDerivationAlgorithm<T>
  {
  public:
  	bool ParameterSupported(const char *name) const {return strcmp(name, Name::KeyDerivationParameters()) == 0;}
  	void Derive(const DL_GroupParameters<T> &params, byte *derivedKey, size_t derivedLength, const T &agreedElement, const T &ephemeralPublicKey, const NameValuePairs &parameters) const
  	{
  		SecByteBlock agreedSecret;
  		if (DHAES_MODE)
  		{
  			agreedSecret.New(params.GetEncodedElementSize(true) + params.GetEncodedElementSize(false));
  			params.EncodeElement(true, ephemeralPublicKey, agreedSecret);
  			params.EncodeElement(false, agreedElement, agreedSecret + params.GetEncodedElementSize(true));
  		}
  		else
  		{
  			agreedSecret.New(params.GetEncodedElementSize(false));
  			params.EncodeElement(false, agreedElement, agreedSecret);
  		}
  
  		ConstByteArrayParameter derivationParameters;
  		parameters.GetValue(Name::KeyDerivationParameters(), derivationParameters);
  		KDF::DeriveKey(derivedKey, derivedLength, agreedSecret, agreedSecret.size(), derivationParameters.begin(), derivationParameters.size());
  	}
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DL_KeyDerivationAlgorithm_P1363() {}
  #endif
  };
  
  //! Discrete Log Integrated Encryption Scheme, AKA <a href="http://www.weidai.com/scan-mirror/ca.html#DLIES">DLIES</a>
  template <class COFACTOR_OPTION = NoCofactorMultiplication, bool DHAES_MODE = true>
  struct DLIES
  	: public DL_ES<
  		DL_CryptoKeys_GFP,
  		DL_KeyAgreementAlgorithm_DH<Integer, COFACTOR_OPTION>,
  		DL_KeyDerivationAlgorithm_P1363<Integer, DHAES_MODE, P1363_KDF2<SHA1> >,
  		DL_EncryptionAlgorithm_Xor<HMAC<SHA1>, DHAES_MODE>,
  		DLIES<> >
  {
  	static std::string CRYPTOPP_API StaticAlgorithmName() {return "DLIES";}	// TODO: fix this after name is standardized
  
  #ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
  	virtual ~DLIES() {}
  #endif
  };
  
  NAMESPACE_END
  
  #if CRYPTOPP_MSC_VERSION
  # pragma warning(pop)
  #endif
  
  #endif
  