text: #ifndef CRYPTOPP_XTRCRYPT_H
  #define CRYPTOPP_XTRCRYPT_H
  
  /** \file
  	"The XTR public key system" by Arjen K. Lenstra and Eric R. Verheul
  */
  
  #include "cryptlib.h"
  #include "xtr.h"
  #include "integer.h"
  
  NAMESPACE_BEGIN(CryptoPP)
  
  //! XTR-DH with key validation
  
  class XTR_DH : public SimpleKeyAgreementDomain, public CryptoParameters
  {
  	typedef XTR_DH ThisClass;
  
  public:
  	XTR_DH(const Integer &p, const Integer &q, const GFP2Element &g);
  	XTR_DH(RandomNumberGenerator &rng, unsigned int pbits, unsigned int qbits);
  	XTR_DH(BufferedTransformation &domainParams);
  
  	void DEREncode(BufferedTransformation &domainParams) const;
  
  	bool Validate(RandomNumberGenerator &rng, unsigned int level) const;
  	bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const;
  	void AssignFrom(const NameValuePairs &source);
  	CryptoParameters & AccessCryptoParameters() {return *this;}
  	unsigned int AgreedValueLength() const {return 2*m_p.ByteCount();}
  	unsigned int PrivateKeyLength() const {return m_q.ByteCount();}
  	unsigned int PublicKeyLength() const {return 2*m_p.ByteCount();}
  
  	void GeneratePrivateKey(RandomNumberGenerator &rng, byte *privateKey) const;
  	void GeneratePublicKey(RandomNumberGenerator &rng, const byte *privateKey, byte *publicKey) const;
  	bool Agree(byte *agreedValue, const byte *privateKey, const byte *otherPublicKey, bool validateOtherPublicKey=true) const;
  
  	const Integer &GetModulus() const {return m_p;}
  	const Integer &GetSubgroupOrder() const {return m_q;}
  	const GFP2Element &GetSubgroupGenerator() const {return m_g;}
  
  	void SetModulus(const Integer &p) {m_p = p;}
  	void SetSubgroupOrder(const Integer &q) {m_q = q;}
  	void SetSubgroupGenerator(const GFP2Element &g) {m_g = g;}
  
  private:
  	unsigned int ExponentBitLength() const;
  
  	Integer m_p, m_q;
  	GFP2Element m_g;
  };
  
  NAMESPACE_END
  
  #endif
  