Interface for Discrete Log (DL) group parameters. More...

#include <pubkey.h>

Inheritance diagram for DL_GroupParameters< T >:

Public Types
typedef T	Element

Public Member Functions
bool	Validate (RandomNumberGenerator &rng, unsigned int level) const
	Check this object for errors.

bool	GetVoidValue (const char name, const std::type_info &valueType, void pValue) const
	Get a named value.

bool	SupportsPrecomputation () const
	Determines whether the object supports precomputation.

void	Precompute (unsigned int precomputationStorage=16)
	Perform precomputation.

void	LoadPrecomputation (BufferedTransformation &storedPrecomputation)
	Retrieve previously saved precomputation.

void	SavePrecomputation (BufferedTransformation &storedPrecomputation) const
	Save precomputation for later use.

virtual const Element &	GetSubgroupGenerator () const
	Retrieves the subgroup generator.

virtual void	SetSubgroupGenerator (const Element &base)
	Sets the subgroup generator.

virtual Element	ExponentiateBase (const Integer &exponent) const
	Exponentiates the base.

virtual Element	ExponentiateElement (const Element &base, const Integer &exponent) const
	Exponentiates an element.

virtual const DL_GroupPrecomputation< Element > &	GetGroupPrecomputation () const =0
	Retrieves the group precomputation.

virtual const DL_FixedBasePrecomputation< Element > &	GetBasePrecomputation () const =0
	Retrieves the group precomputation.

virtual DL_FixedBasePrecomputation< Element > &	AccessBasePrecomputation ()=0
	Retrieves the group precomputation.

virtual const Integer &	GetSubgroupOrder () const =0
	Retrieves the subgroup order.

virtual Integer	GetMaxExponent () const =0
	Retrieves the maximum exponent for the group.

virtual Integer	GetGroupOrder () const
	Retrieves the order of the group.

virtual Integer	GetCofactor () const
	Retrieves the cofactor.

virtual unsigned int	GetEncodedElementSize (bool reversible) const =0
	Retrieves the encoded element's size.

virtual void	EncodeElement (bool reversible, const Element &element, byte *encoded) const =0
	Encodes the element.

virtual Element	DecodeElement (const byte *encoded, bool checkForGroupMembership) const =0
	Decodes the element.

virtual Integer	ConvertElementToInteger (const Element &element) const =0
	Converts an element to an Integer.

virtual bool	ValidateGroup (RandomNumberGenerator &rng, unsigned int level) const =0
	Check the group for errors.

virtual bool	ValidateElement (unsigned int level, const Element &element, const DL_FixedBasePrecomputation< Element > *precomp) const =0
	Check the element for errors.

virtual bool	FastSubgroupCheckAvailable () const =0

virtual bool	IsIdentity (const Element &element) const =0
	Determines if an element is an identity.

virtual void	SimultaneousExponentiate (Element results, const Element &base, const Integer exponents, unsigned int exponentsCount) const =0
	Exponentiates a base to multiple exponents.

Public Member Functions inherited from GeneratableCryptoMaterial
virtual void	GenerateRandom (RandomNumberGenerator &rng, const NameValuePairs &params=g_nullNameValuePairs)
	Generate a random key or crypto parameters.

void	GenerateRandomWithKeySize (RandomNumberGenerator &rng, unsigned int keySize)
	Generate a random key or crypto parameters.

Public Member Functions inherited from CryptoMaterial
virtual void	AssignFrom (const NameValuePairs &source)=0
	Assign values to this object.

virtual void	ThrowIfInvalid (RandomNumberGenerator &rng, unsigned int level) const
	Check this object for errors.

virtual void	Save (BufferedTransformation &bt) const
	Saves a key to a BufferedTransformation.

virtual void	Load (BufferedTransformation &bt)
	Loads a key from a BufferedTransformation.

void	DoQuickSanityCheck () const
	Perform a quick sanity check.

Public Member Functions inherited from NameValuePairs
template<class T >
bool	GetThisObject (T &object) const
	Get a copy of this object or subobject.

template<class T >
bool	GetThisPointer (T *&ptr) const
	Get a pointer to this object.

template<class T >
bool	GetValue (const char *name, T &value) const
	Get a named value.

template<class T >
T	GetValueWithDefault (const char *name, T defaultValue) const
	Get a named value.

CRYPTOPP_DLL std::string	GetValueNames () const
	Get a list of value names that can be retrieved.

CRYPTOPP_DLL bool	GetIntValue (const char *name, int &value) const
	Get a named value with type int.

CRYPTOPP_DLL int	GetIntValueWithDefault (const char *name, int defaultValue) const
	Get a named value with type int, with default.

CRYPTOPP_DLL bool	GetWord64Value (const char *name, word64 &value) const
	Get a named value with type word64.

CRYPTOPP_DLL word64	GetWord64ValueWithDefault (const char *name, word64 defaultValue) const
	Get a named value with type word64, with default.

template<class T >
void	GetRequiredParameter (const char className, const char name, T &value) const
	Retrieves a required name/value pair.

CRYPTOPP_DLL void	GetRequiredIntParameter (const char className, const char name, int &value) const
	Retrieves a required name/value pair.

Additional Inherited Members
Static Public Member Functions inherited from NameValuePairs
static CRYPTOPP_DLL void	ThrowIfTypeMismatch (const char *name, const std::type_info &stored, const std::type_info &retrieving)
	Ensures an expected name and type is present.

Detailed Description

template<class T>
class DL_GroupParameters< T >

Interface for Discrete Log (DL) group parameters.

Template Parameters

T	element in the group

The element is usually an Integer, ECP::Point or EC2N::Point

Definition at line 781 of file pubkey.h.

Member Typedef Documentation

◆ Element

template<class T >

typedef T DL_GroupParameters< T >::Element

Definition at line 786 of file pubkey.h.

Constructor & Destructor Documentation

◆ ~DL_GroupParameters()

template<class T >

virtual DL_GroupParameters< T >::~DL_GroupParameters ( )

inlinevirtual

Definition at line 788 of file pubkey.h.

◆ DL_GroupParameters()

template<class T >

DL_GroupParameters< T >::DL_GroupParameters ( )

inline

Definition at line 790 of file pubkey.h.

Member Function Documentation

◆ Validate()

template<class T >

bool DL_GroupParameters< T >::Validate	(	RandomNumberGenerator &	rng,
		unsigned int	level ) const

inlinevirtual

Check this object for errors.

Parameters

rng	a RandomNumberGenerator for objects which use randomized testing
level	the level of thoroughness

Returns: true if the tests succeed, false otherwise

There are four levels of thoroughness:

0 - using this object won't cause a crash or exception
1 - this object will probably function, and encrypt, sign, other operations correctly
2 - ensure this object will function correctly, and perform reasonable security checks
3 - perform reasonable security checks, and do checks that may take a long time

Level 0 does not require a RandomNumberGenerator. A NullRNG() can be used for level 0. Level 1 may not check for weak keys and such. Levels 2 and 3 are recommended.

See also: ThrowIfInvalid()

Implements CryptoMaterial.

Definition at line 793 of file pubkey.h.

◆ GetVoidValue()

template<class T >

bool DL_GroupParameters< T >::GetVoidValue	(	const char *	name,
		const std::type_info &	valueType,
		void *	pValue ) const

inlinevirtual

Get a named value.

Parameters

name	the name of the object or value to retrieve
valueType	reference to a variable that receives the value
pValue	void pointer to a variable that receives the value

Returns: true if the value was retrieved, false otherwise

GetVoidValue() retrieves the value of name if it exists.

Note: GetVoidValue() is an internal function and should be implemented by derived classes. Users should use one of the other functions instead.

See also: GetValue(), GetValueWithDefault(), GetIntValue(), GetIntValueWithDefault(), GetRequiredParameter() and GetRequiredIntParameter()

Implements NameValuePairs.

Reimplemented in DL_GroupParameters_EC< EC >, DL_GroupParameters_IntegerBased, DL_GroupParameters_IntegerBasedImpl< GROUP_PRECOMP, BASE_PRECOMP >, DL_GroupParameters_IntegerBasedImpl< DL_GroupPrecomputation_LUC, DL_BasePrecomputation_LUC >, DL_GroupParameters_IntegerBasedImpl< ModExpPrecomputation >, DL_GroupParameters_GFP, and DL_GroupParameters_LUC.

Definition at line 811 of file pubkey.h.

◆ SupportsPrecomputation()

template<class T >

bool DL_GroupParameters< T >::SupportsPrecomputation ( ) const

inlinevirtual

Determines whether the object supports precomputation.

Returns: true if the object supports precomputation, false otherwise

See also: Precompute()

Reimplemented from CryptoMaterial.

Definition at line 822 of file pubkey.h.

◆ Precompute()

template<class T >

void DL_GroupParameters< T >::Precompute ( unsigned int precomputationStorage = 16 )

inlinevirtual

Perform precomputation.

Parameters

precomputationStorage the suggested number of objects for the precompute table

Exceptions

NotImplemented

The exact semantics of Precompute() varies, but it typically means calculate a table of n objects that can be used later to speed up computation.

If a derived class does not override Precompute(), then the base class throws NotImplemented.

See also: SupportsPrecomputation(), LoadPrecomputation(), SavePrecomputation()

Reimplemented from CryptoMaterial.

Definition at line 832 of file pubkey.h.

◆ LoadPrecomputation()

template<class T >

void DL_GroupParameters< T >::LoadPrecomputation ( BufferedTransformation & storedPrecomputation )

inlinevirtual

Retrieve previously saved precomputation.

Parameters

storedPrecomputation BufferedTransformation with the saved precomputation

Exceptions

NotImplemented

See also: SupportsPrecomputation(), Precompute()

Reimplemented from CryptoMaterial.

Definition at line 841 of file pubkey.h.

◆ SavePrecomputation()

template<class T >

void DL_GroupParameters< T >::SavePrecomputation ( BufferedTransformation & storedPrecomputation ) const

inlinevirtual

Save precomputation for later use.

Parameters

storedPrecomputation BufferedTransformation to write the precomputation

Exceptions

NotImplemented

See also: SupportsPrecomputation(), Precompute()

Reimplemented from CryptoMaterial.

Definition at line 851 of file pubkey.h.

◆ GetSubgroupGenerator()

template<class T >

virtual const Element & DL_GroupParameters< T >::GetSubgroupGenerator ( ) const

inlinevirtual

Retrieves the subgroup generator.

Returns: the subgroup generator

The subgroup generator is retrieved from the base precomputation

Definition at line 859 of file pubkey.h.

◆ SetSubgroupGenerator()

template<class T >

virtual void DL_GroupParameters< T >::SetSubgroupGenerator ( const Element & base )

inlinevirtual

Sets the subgroup generator.

Parameters

base	the new subgroup generator

The subgroup generator is set in the base precomputation

Definition at line 864 of file pubkey.h.

◆ ExponentiateBase()

template<class T >

virtual Element DL_GroupParameters< T >::ExponentiateBase ( const Integer & exponent ) const

inlinevirtual

Exponentiates the base.

Returns: the element after exponentiation

ExponentiateBase() calls GetBasePrecomputation() and then exponentiates.

Definition at line 869 of file pubkey.h.

◆ ExponentiateElement()

template<class T >

virtual Element DL_GroupParameters< T >::ExponentiateElement	(	const Element &	base,
		const Integer &	exponent ) const

inlinevirtual

Exponentiates an element.

Parameters

base	the base element
exponent	the exponent to raise the base

Returns: the result of the exponentiation

Internally, ExponentiateElement() calls SimultaneousExponentiate().

Definition at line 879 of file pubkey.h.

◆ GetGroupPrecomputation()

template<class T >

virtual const DL_GroupPrecomputation< Element > & DL_GroupParameters< T >::GetGroupPrecomputation ( ) const

pure virtual

Retrieves the group precomputation.

Returns: a const reference to the group precomputation

Implemented in DL_GroupParametersImpl< GROUP_PRECOMP, BASE_PRECOMP, BASE >, DL_GroupParametersImpl< DL_GroupPrecomputation_LUC, DL_BasePrecomputation_LUC, DL_GroupParameters_IntegerBased >, DL_GroupParametersImpl< EcPrecomputation< EC > >, DL_GroupParametersImpl< GROUP_PRECOMP, DL_FixedBasePrecomputationImpl< typename GROUP_PRECOMP::Element >, DL_GroupParameters_IntegerBased >, and DL_GroupParametersImpl< ModExpPrecomputation, DL_FixedBasePrecomputationImpl< typename GROUP_PRECOMP::Element >, DL_GroupParameters_IntegerBased >.

◆ GetBasePrecomputation()

template<class T >

virtual const DL_FixedBasePrecomputation< Element > & DL_GroupParameters< T >::GetBasePrecomputation ( ) const

pure virtual

Retrieves the group precomputation.

Returns: a const reference to the group precomputation using a fixed base

◆ AccessBasePrecomputation()

template<class T >

virtual DL_FixedBasePrecomputation< Element > & DL_GroupParameters< T >::AccessBasePrecomputation ( )

pure virtual

Retrieves the group precomputation.

Returns: a non-const reference to the group precomputation using a fixed base

◆ GetSubgroupOrder()

template<class T >

virtual const Integer & DL_GroupParameters< T >::GetSubgroupOrder ( ) const

pure virtual

Retrieves the subgroup order.

Returns: the order of subgroup generated by the base element

Implemented in DL_GroupParameters_EC< EC >, and DL_GroupParameters_IntegerBased.

◆ GetMaxExponent()

template<class T >

virtual Integer DL_GroupParameters< T >::GetMaxExponent ( ) const

pure virtual

Retrieves the maximum exponent for the group.

Returns: the maximum exponent for the group

Implemented in DL_GroupParameters_EC< EC >, DL_GroupParameters_IntegerBased, and DL_GroupParameters_ElGamal.

◆ GetGroupOrder()

template<class T >

virtual Integer DL_GroupParameters< T >::GetGroupOrder ( ) const

inlinevirtual

Retrieves the order of the group.

Returns: the order of the group

Either GetGroupOrder() or GetCofactor() must be overridden in a derived class.

Reimplemented in DL_GroupParameters_IntegerBased.

Definition at line 909 of file pubkey.h.

◆ GetCofactor()

template<class T >

virtual Integer DL_GroupParameters< T >::GetCofactor ( ) const

inlinevirtual

Retrieves the cofactor.

Returns: the cofactor

Either GetGroupOrder() or GetCofactor() must be overridden in a derived class.

Reimplemented in DL_GroupParameters_EC< EC >.

Definition at line 914 of file pubkey.h.

◆ GetEncodedElementSize()

template<class T >

virtual unsigned int DL_GroupParameters< T >::GetEncodedElementSize ( bool reversible ) const

pure virtual

Retrieves the encoded element's size.

Parameters

reversible flag indicating the encoding format

Returns: encoded element's size, in bytes

The format of the encoded element varies by the underlying type of the element and the reversible flag. GetEncodedElementSize() must be implemented in a derived class.

See also: GetEncodedElementSize(), EncodeElement(), DecodeElement()

Implemented in DL_GroupParameters_EC< EC >, and DL_GroupParameters_IntegerBased.

◆ EncodeElement()

template<class T >

virtual void DL_GroupParameters< T >::EncodeElement	(	bool	reversible,
		const Element &	element,
		byte *	encoded ) const

pure virtual

Encodes the element.

Parameters

reversible	flag indicating the encoding format
element	reference to the element to encode
encoded	destination byte array for the encoded element

EncodeElement() must be implemented in a derived class.

Precondition: COUNTOF(encoded) == GetEncodedElementSize()

Implemented in DL_GroupParameters_IntegerBased.

◆ DecodeElement()

template<class T >

virtual Element DL_GroupParameters< T >::DecodeElement	(	const byte *	encoded,
		bool	checkForGroupMembership ) const

pure virtual

Decodes the element.

Parameters

encoded	byte array with the encoded element
checkForGroupMembership	flag indicating if the element should be validated

Returns: Element after decoding

DecodeElement() must be implemented in a derived class.

Precondition: COUNTOF(encoded) == GetEncodedElementSize()

Implemented in DL_GroupParameters_EC< EC >, and DL_GroupParameters_IntegerBased.

◆ ConvertElementToInteger()

template<class T >

virtual Integer DL_GroupParameters< T >::ConvertElementToInteger ( const Element & element ) const

pure virtual

Converts an element to an Integer.

Parameters

element the element to convert to an Integer

Returns: Element after converting to an Integer

ConvertElementToInteger() must be implemented in a derived class.

Implemented in DL_GroupParameters_IntegerBased.

◆ ValidateGroup()

template<class T >

virtual bool DL_GroupParameters< T >::ValidateGroup	(	RandomNumberGenerator &	rng,
		unsigned int	level ) const

pure virtual

Check the group for errors.

Parameters

rng	RandomNumberGenerator for objects which use randomized testing
level	level of thoroughness

Returns: true if the tests succeed, false otherwise

There are four levels of thoroughness:

0 - using this object won't cause a crash or exception
1 - this object will probably function, and encrypt, sign, other operations correctly
2 - ensure this object will function correctly, and perform reasonable security checks
3 - perform reasonable security checks, and do checks that may take a long time

Level 0 does not require a RandomNumberGenerator. A NullRNG() can be used for level 0. Level 1 may not check for weak keys and such. Levels 2 and 3 are recommended.

ValidateGroup() must be implemented in a derived class.

Implemented in DL_GroupParameters_EC< EC >, DL_GroupParameters_IntegerBased, and DL_GroupParameters_DSA.

◆ ValidateElement()

template<class T >

virtual bool DL_GroupParameters< T >::ValidateElement	(	unsigned int	level,
		const Element &	element,
		const DL_FixedBasePrecomputation< Element > *	precomp ) const

pure virtual

Check the element for errors.

Parameters

level	level of thoroughness
element	element to check
precomp	optional pointer to DL_FixedBasePrecomputation

Returns: true if the tests succeed, false otherwise

There are four levels of thoroughness:

0 - using this object won't cause a crash or exception
1 - this object will probably function, and encrypt, sign, other operations correctly
2 - ensure this object will function correctly, and perform reasonable security checks
3 - perform reasonable security checks, and do checks that may take a long time

Level 0 performs group membership checks. Level 1 may not check for weak keys and such. Levels 2 and 3 are recommended.

ValidateElement() must be implemented in a derived class.

Implemented in DL_GroupParameters_IntegerBased.

◆ FastSubgroupCheckAvailable()

template<class T >

virtual bool DL_GroupParameters< T >::FastSubgroupCheckAvailable ( ) const

pure virtual

Implemented in DL_GroupParameters_IntegerBased.

◆ IsIdentity()

template<class T >

virtual bool DL_GroupParameters< T >::IsIdentity ( const Element & element ) const

pure virtual

Determines if an element is an identity.

Parameters

element element to check

Returns: true if the element is an identity, false otherwise

The identity element or or neutral element is a special element in a group that leaves other elements unchanged when combined with it.

IsIdentity() must be implemented in a derived class.

◆ SimultaneousExponentiate()

template<class T >

virtual void DL_GroupParameters< T >::SimultaneousExponentiate	(	Element *	results,
		const Element &	base,
		const Integer *	exponents,
		unsigned int	exponentsCount ) const

pure virtual

Exponentiates a base to multiple exponents.

Parameters

results	an array of Elements
base	the base to raise to the exponents
exponents	an array of exponents
exponentsCount	the number of exponents in the array

SimultaneousExponentiate() raises the base to each exponent in the exponents array and stores the result at the respective position in the results array.

SimultaneousExponentiate() must be implemented in a derived class.

Precondition: COUNTOF(results) == exponentsCount; COUNTOF(exponents) == exponentsCount

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

pubkey.h

Public Types

Public Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ Element

Constructor & Destructor Documentation

◆ ~DL_GroupParameters()

◆ DL_GroupParameters()

Member Function Documentation

◆ Validate()

◆ GetVoidValue()

◆ SupportsPrecomputation()

◆ Precompute()

◆ LoadPrecomputation()

◆ SavePrecomputation()

◆ GetSubgroupGenerator()

◆ SetSubgroupGenerator()

◆ ExponentiateBase()

◆ ExponentiateElement()

◆ GetGroupPrecomputation()

◆ GetBasePrecomputation()

◆ AccessBasePrecomputation()

◆ GetSubgroupOrder()

◆ GetMaxExponent()

◆ GetGroupOrder()

◆ GetCofactor()

◆ GetEncodedElementSize()

◆ EncodeElement()

◆ DecodeElement()

◆ ConvertElementToInteger()

◆ ValidateGroup()

◆ ValidateElement()

◆ FastSubgroupCheckAvailable()

◆ IsIdentity()

◆ SimultaneousExponentiate()