Diffie-Hellman in GF(p) More...

#include <dh.h>

Inheritance diagram for DH:

Public Types
typedef DH_Domain< DL_GroupParameters_GFP_DefaultSafePrime >	GroupParameters

typedef GroupParameters::Element	Element

Public Types inherited from DH_Domain< DL_GroupParameters_GFP_DefaultSafePrime >
typedef DL_GroupParameters_GFP_DefaultSafePrime	GroupParameters

typedef GroupParameters::Element	Element

typedef DL_KeyAgreementAlgorithm_DH< Element, typename GROUP_PARAMETERS::DefaultCofactorOption >	DH_Algorithm

typedef DH_Domain< DL_GroupParameters_GFP_DefaultSafePrime, typename GROUP_PARAMETERS::DefaultCofactorOption >	Domain

Public Types inherited from DL_SimpleKeyAgreementDomainBase< GROUP_PARAMETERS::Element >
typedef GROUP_PARAMETERS::Element	Element

Public Member Functions
	DH ()
	Create an uninitialized Diffie-Hellman object.

	DH (BufferedTransformation &bt)
	Initialize a Diffie-Hellman object.

	DH (const GroupParameters &params)
	Initialize a Diffie-Hellman object.

	DH (RandomNumberGenerator &rng, unsigned int modulusBits)
	Create a Diffie-Hellman object.

	DH (const Integer &p, const Integer &g)
	Initialize a Diffie-Hellman object.

	DH (const Integer &p, const Integer &q, const Integer &g)
	Initialize a Diffie-Hellman object.

void	Initialize (RandomNumberGenerator &rng, unsigned int modulusBits)
	Creates a Diffie-Hellman object.

void	Initialize (const Integer &p, const Integer &g)
	Initialize a Diffie-Hellman object.

void	Initialize (const Integer &p, const Integer &q, const Integer &g)
	Initialize a Diffie-Hellman object.

Public Member Functions inherited from DH_Domain< DL_GroupParameters_GFP_DefaultSafePrime >
	DH_Domain ()
	Construct a Diffie-Hellman domain.

	DH_Domain (const GroupParameters &params)
	Construct a Diffie-Hellman domain.

	DH_Domain (BufferedTransformation &bt)
	Construct a Diffie-Hellman domain.

	DH_Domain (RandomNumberGenerator &v1, const T2 &v2)
	Create a Diffie-Hellman domain.

	DH_Domain (RandomNumberGenerator &v1, const T2 &v2, const T3 &v3)
	Create a Diffie-Hellman domain.

	DH_Domain (RandomNumberGenerator &v1, const T2 &v2, const T3 &v3, const T4 &v4)
	Create a Diffie-Hellman domain.

	DH_Domain (const T1 &v1, const T2 &v2)
	Construct a Diffie-Hellman domain.

	DH_Domain (const T1 &v1, const T2 &v2, const T3 &v3)
	Construct a Diffie-Hellman domain.

	DH_Domain (const T1 &v1, const T2 &v2, const T3 &v3, const T4 &v4)
	Construct a Diffie-Hellman domain.

const GroupParameters &	GetGroupParameters () const
	Retrieves the group parameters for this domain.

GroupParameters &	AccessGroupParameters ()
	Retrieves the group parameters for this domain.

void	GeneratePublicKey (RandomNumberGenerator &rng, const byte privateKey, byte publicKey) const
	Generate a public key from a private key in this domain.

std::string	AlgorithmName () const
	Provides the name of this algorithm.

Public Member Functions inherited from DL_SimpleKeyAgreementDomainBase< GROUP_PARAMETERS::Element >
CryptoParameters &	AccessCryptoParameters ()
	Retrieves a reference to Crypto Parameters.

unsigned int	AgreedValueLength () const
	Provides the size of the agreed value.

unsigned int	PrivateKeyLength () const
	Provides the size of the private key.

unsigned int	PublicKeyLength () const
	Provides the size of the public key.

void	GeneratePrivateKey (RandomNumberGenerator &rng, byte *privateKey) const
	Generate private key in this domain.

void	GeneratePublicKey (RandomNumberGenerator &rng, const byte privateKey, byte publicKey) const
	Generate a public key from a private key in this domain.

bool	Agree (byte agreedValue, const byte privateKey, const byte *otherPublicKey, bool validateOtherPublicKey=true) const
	Derive agreed value.

const Element &	GetGenerator () const
	Retrieves a reference to the group generator.

Public Member Functions inherited from SimpleKeyAgreementDomain
virtual void	GenerateKeyPair (RandomNumberGenerator &rng, byte privateKey, byte publicKey) const
	Generate a private/public key pair.

Public Member Functions inherited from KeyAgreementAlgorithm
CryptoMaterial &	AccessMaterial ()
	Retrieves a reference to Crypto Parameters.

const CryptoMaterial &	GetMaterial () const
	Retrieves a reference to Crypto Parameters.

virtual const CryptoParameters &	GetCryptoParameters () const
	Retrieves a reference to Crypto Parameters.

Public Member Functions inherited from Algorithm
	Algorithm (bool checkSelfTestStatus=true)
	Interface for all crypto algorithms.

virtual std::string	AlgorithmProvider () const
	Retrieve the provider of this algorithm.

Public Member Functions inherited from Clonable
virtual Clonable *	Clone () const
	Copies this object.

Additional Inherited Members
Static Public Member Functions inherited from DH_Domain< DL_GroupParameters_GFP_DefaultSafePrime >
static std::string	StaticAlgorithmName ()

Detailed Description

Diffie-Hellman in GF(p)

DH() class is a typedef of DH_Domain(). The documentation that follows does not exist. Rather the documentation was created in response to Issue 328, Diffie-Hellman example code not compiling.

Generally speaking, a DH() object is ephemeral and is intended to execute one instance of the Diffie-Hellman protocol. The private and public key parts are not intended to be set or persisted. Rather, a new set of domain parameters are generated each time an object is created.

Once a DH() object is created, once can retrieve the ephemeral public key for the other party with code similar to the following.

   AutoSeededRandomPool prng;
  Integer p, q, g;
  PrimeAndGenerator pg;

  pg.Generate(1, prng, 512, 511);
  p = pg.Prime();
  q = pg.SubPrime();
  g = pg.Generator();

  DH dh(p, q, g);
  SecByteBlock t1(dh.PrivateKeyLength()), t2(dh.PublicKeyLength());
  dh.GenerateKeyPair(prng, t1, t2);
  Integer k1(t1, t1.size()), k2(t2, t2.size());

  cout << "Private key:\n";
  cout << hex << k1 << endl;

  cout << "Public key:\n";
  cout << hex << k2 << endl;

Output of the program above will be similar to the following.

   $ ./cryptest.exe
  Private key:
  72b45a42371545e9d4880f48589aefh
  Public key:
  45fdb13f97b1840626f0250cec1dba4a23b894100b51fb5d2dd13693d789948f8bfc88f9200014b2
  ba8dd8a6debc471c69ef1e2326c61184a2eca88ec866346bh

See also: Diffie-Hellman on the Crypto++ wiki and Diffie-Hellman in GF(p) with key validation

Since: Crypto++ 1.0

Definition at line 211 of file dh.h.

Member Typedef Documentation

◆ GroupParameters

typedef DH_Domain<DL_GroupParameters_GFP_DefaultSafePrime> DH::GroupParameters

Definition at line 213 of file dh.h.

◆ Element

typedef GroupParameters::Element DH::Element

Definition at line 214 of file dh.h.

Constructor & Destructor Documentation

◆ ~DH()

virtual DH::~DH ( )

inlinevirtual

Definition at line 216 of file dh.h.

◆ DH() [1/6]

DH::DH ( )

inline

Create an uninitialized Diffie-Hellman object.

Definition at line 219 of file dh.h.

◆ DH() [2/6]

DH::DH ( BufferedTransformation & bt )

inline

Initialize a Diffie-Hellman object.

Parameters

bt	BufferedTransformation with group parameters and options

Definition at line 223 of file dh.h.

◆ DH() [3/6]

DH::DH ( const GroupParameters & params )

inline

Initialize a Diffie-Hellman object.

Parameters

params group parameters and options

Definition at line 227 of file dh.h.

◆ DH() [4/6]

DH::DH	(	RandomNumberGenerator &	rng,
		unsigned int	modulusBits )

inline

Create a Diffie-Hellman object.

Parameters

rng	a RandomNumberGenerator derived class
modulusBits	the size of the modulus, in bits

This function overload of Initialize() creates a new Diffie-Hellman object because it takes a RandomNumberGenerator() as a parameter.

Definition at line 234 of file dh.h.

◆ DH() [5/6]

DH::DH	(	const Integer &	p,
		const Integer &	g )

inline

Initialize a Diffie-Hellman object.

Parameters

p	the modulus
g	the generator

Definition at line 239 of file dh.h.

◆ DH() [6/6]

DH::DH	(	const Integer &	p,
		const Integer &	q,
		const Integer &	g )

inline

Initialize a Diffie-Hellman object.

Parameters

p	the modulus
q	the subgroup order
g	the generator

Definition at line 245 of file dh.h.

Member Function Documentation

◆ Initialize() [1/3]

void DH::Initialize	(	RandomNumberGenerator &	rng,
		unsigned int	modulusBits )

inline

Creates a Diffie-Hellman object.

Parameters

rng	a RandomNumberGenerator derived class
modulusBits	the size of the modulus, in bits

This function overload of Initialize() creates a new Diffie-Hellman object because it takes a RandomNumberGenerator() as a parameter.

Definition at line 252 of file dh.h.

◆ Initialize() [2/3]

void DH::Initialize	(	const Integer &	p,
		const Integer &	g )

inline

Initialize a Diffie-Hellman object.

Parameters

p	the modulus
g	the generator

Definition at line 258 of file dh.h.

◆ Initialize() [3/3]

void DH::Initialize	(	const Integer &	p,
		const Integer &	q,
		const Integer &	g )

inline

Initialize a Diffie-Hellman object.

Parameters

p	the modulus
q	the subgroup order
g	the generator

Definition at line 265 of file dh.h.

The documentation for this struct was generated from the following file:

dh.h

Public Types

Public Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ GroupParameters

◆ Element

Constructor & Destructor Documentation

◆ ~DH()

◆ DH() [1/6]

◆ DH() [2/6]

◆ DH() [3/6]

◆ DH() [4/6]

◆ DH() [5/6]

◆ DH() [6/6]

Member Function Documentation

◆ Initialize() [1/3]

◆ Initialize() [2/3]

◆ Initialize() [3/3]