Elliptic Curve Parameters. More...

#include <eccrypto.h>

Inheritance diagram for DL_GroupParameters_EC< EC >:

Public Types
typedef EC	EllipticCurve

typedef EllipticCurve::Point	Point

typedef Point	Element

typedef IncompatibleCofactorMultiplication	DefaultCofactorOption

Public Types inherited from DL_GroupParametersImpl< EcPrecomputation< EC > >
typedef EcPrecomputation< EC >	GroupPrecomputation

typedef GROUP_PRECOMP::Element	Element

typedef DL_FixedBasePrecomputationImpl< typename GROUP_PRECOMP::Element >	BasePrecomputation

Public Types inherited from DL_GroupParameters< T >
typedef T	Element

Public Member Functions
	DL_GroupParameters_EC ()
	Construct an EC GroupParameters.

	DL_GroupParameters_EC (const OID &oid)
	Construct an EC GroupParameters.

	DL_GroupParameters_EC (const EllipticCurve &ec, const Point &G, const Integer &n, const Integer &k=Integer::Zero())
	Construct an EC GroupParameters.

	DL_GroupParameters_EC (BufferedTransformation &bt)
	Construct an EC GroupParameters.

void	Initialize (const EllipticCurve &ec, const Point &G, const Integer &n, const Integer &k=Integer::Zero())
	Initialize an EC GroupParameters using {EC,G,n,k}.

void	Initialize (const OID &oid)
	Initialize a DL_GroupParameters_EC {EC,G,n,k}.

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

void	AssignFrom (const NameValuePairs &source)
	Assign values to this object.

void	GenerateRandom (RandomNumberGenerator &rng, const NameValuePairs &alg)
	this implementation doesn't actually generate a curve, it just initializes the parameters with existing values

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

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

const Integer &	GetSubgroupOrder () const
	Retrieves the subgroup order.

Integer	GetCofactor () const
	Retrieves the cofactor.

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

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

bool	FastSubgroupCheckAvailable () const

void	EncodeElement (bool reversible, const Element &element, byte *encoded) const

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

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

Integer	ConvertElementToInteger (const Element &element) const

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

bool	IsIdentity (const Element &element) const

void	SimultaneousExponentiate (Element results, const Element &base, const Integer exponents, unsigned int exponentsCount) const

OID	GetAlgorithmID () const

Element	MultiplyElements (const Element &a, const Element &b) const

Element	CascadeExponentiate (const Element &element1, const Integer &exponent1, const Element &element2, const Integer &exponent2) const

void	BERDecode (BufferedTransformation &bt)

void	DEREncode (BufferedTransformation &bt) const

void	SetPointCompression (bool compress)

bool	GetPointCompression () const

void	SetEncodeAsOID (bool encodeAsOID)

bool	GetEncodeAsOID () const

const EllipticCurve &	GetCurve () const

bool	operator== (const ThisClass &rhs) const

Public Member Functions inherited from DL_GroupParametersImpl< EcPrecomputation< EC > >
const DL_GroupPrecomputation< Element > &	GetGroupPrecomputation () const
	Retrieves the group precomputation.

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

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

Public Member Functions inherited from DL_GroupParameters< T >
bool	Validate (RandomNumberGenerator &rng, unsigned int level) const
	Check this object for errors.

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

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

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

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

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

Public Member Functions inherited from CryptoMaterial
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.

Static Public Member Functions
static std::string	StaticAlgorithmNamePrefix ()

static OID	GetNextRecommendedParametersOID (const OID &oid)

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 EC>
class DL_GroupParameters_EC< EC >

Elliptic Curve Parameters.

Template Parameters

EC	elliptic curve field

This class corresponds to the ASN.1 sequence of the same name in ANSI X9.62 and SEC 1. EC is currently defined for ECP and EC2N.

Definition at line 39 of file eccrypto.h.

Member Typedef Documentation

◆ EllipticCurve

template<class EC >

typedef EC DL_GroupParameters_EC< EC >::EllipticCurve

Definition at line 44 of file eccrypto.h.

◆ Point

template<class EC >

typedef EllipticCurve::Point DL_GroupParameters_EC< EC >::Point

Definition at line 45 of file eccrypto.h.

◆ Element

template<class EC >

typedef Point DL_GroupParameters_EC< EC >::Element

Definition at line 46 of file eccrypto.h.

◆ DefaultCofactorOption

template<class EC >

typedef IncompatibleCofactorMultiplication DL_GroupParameters_EC< EC >::DefaultCofactorOption

Definition at line 47 of file eccrypto.h.

Constructor & Destructor Documentation

◆ ~DL_GroupParameters_EC()

template<class EC >

virtual DL_GroupParameters_EC< EC >::~DL_GroupParameters_EC ( )

inlinevirtual

Definition at line 49 of file eccrypto.h.

◆ DL_GroupParameters_EC() [1/4]

template<class EC >

DL_GroupParameters_EC< EC >::DL_GroupParameters_EC ( )

inline

Construct an EC GroupParameters.

Definition at line 52 of file eccrypto.h.

◆ DL_GroupParameters_EC() [2/4]

template<class EC >

DL_GroupParameters_EC< EC >::DL_GroupParameters_EC ( const OID & oid )

inline

Construct an EC GroupParameters.

Parameters

oid	the OID of a curve

Definition at line 56 of file eccrypto.h.

◆ DL_GroupParameters_EC() [3/4]

template<class EC >

DL_GroupParameters_EC< EC >::DL_GroupParameters_EC	(	const EllipticCurve &	ec,
		const Point &	G,
		const Integer &	n,
		const Integer &	k = Integer::Zero() )

inline

Construct an EC GroupParameters.

Parameters

ec	the elliptic curve
G	the base point
n	the order of the base point
k	the cofactor

Definition at line 64 of file eccrypto.h.

◆ DL_GroupParameters_EC() [4/4]

template<class EC >

DL_GroupParameters_EC< EC >::DL_GroupParameters_EC ( BufferedTransformation & bt )

inline

Construct an EC GroupParameters.

Parameters

bt	BufferedTransformation with group parameters

Definition at line 69 of file eccrypto.h.

Member Function Documentation

◆ Initialize() [1/2]

template<class EC >

void DL_GroupParameters_EC< EC >::Initialize	(	const EllipticCurve &	ec,
		const Point &	G,
		const Integer &	n,
		const Integer &	k = Integer::Zero() )

inline

Initialize an EC GroupParameters using {EC,G,n,k}.

Parameters

ec	the elliptic curve
G	the base point
n	the order of the base point
k	the cofactor

This Initialize() function overload initializes group parameters from existing parameters.

Definition at line 78 of file eccrypto.h.

◆ Initialize() [2/2]

template<class EC >

void DL_GroupParameters_EC< EC >::Initialize ( const OID & oid )

Initialize a DL_GroupParameters_EC {EC,G,n,k}.

Parameters

oid	the OID of a curve

This Initialize() function overload initializes group parameters from existing parameters.

◆ GetVoidValue()

template<class EC >

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

virtual

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()

Reimplemented from DL_GroupParameters< T >.

◆ AssignFrom()

template<class EC >

void DL_GroupParameters_EC< EC >::AssignFrom ( const NameValuePairs & source )

virtual

Assign values to this object.

This function can be used to create a public key from a private key.

Implements CryptoMaterial.

◆ GenerateRandom()

template<class EC >

void DL_GroupParameters_EC< EC >::GenerateRandom	(	RandomNumberGenerator &	rng,
		const NameValuePairs &	alg )

virtual

this implementation doesn't actually generate a curve, it just initializes the parameters with existing values

parameters: (Curve, SubgroupGenerator, SubgroupOrder, Cofactor (optional)), or (GroupOID)

Reimplemented from GeneratableCryptoMaterial.

◆ GetBasePrecomputation()

template<class EC >

const DL_FixedBasePrecomputation< Element > & DL_GroupParameters_EC< EC >::GetBasePrecomputation ( ) const

inlinevirtual

Retrieves the group precomputation.

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

Implements DL_GroupParameters< T >.

Definition at line 101 of file eccrypto.h.

◆ AccessBasePrecomputation()

template<class EC >

DL_FixedBasePrecomputation< Element > & DL_GroupParameters_EC< EC >::AccessBasePrecomputation ( )

inlinevirtual

Retrieves the group precomputation.

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

Implements DL_GroupParameters< T >.

Definition at line 102 of file eccrypto.h.

◆ GetSubgroupOrder()

template<class EC >

const Integer & DL_GroupParameters_EC< EC >::GetSubgroupOrder ( ) const

inlinevirtual

Retrieves the subgroup order.

Returns: the order of subgroup generated by the base element

Implements DL_GroupParameters< T >.

Definition at line 103 of file eccrypto.h.

◆ GetCofactor()

template<class EC >

Integer DL_GroupParameters_EC< EC >::GetCofactor ( ) const

virtual

Retrieves the cofactor.

Returns: the cofactor

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

Reimplemented from DL_GroupParameters< T >.

◆ ValidateGroup()

template<class EC >

bool DL_GroupParameters_EC< EC >::ValidateGroup	(	RandomNumberGenerator &	rng,
		unsigned int	level ) const

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.

Implements DL_GroupParameters< T >.

◆ FastSubgroupCheckAvailable()

template<class EC >

bool DL_GroupParameters_EC< EC >::FastSubgroupCheckAvailable ( ) const

inlinevirtual

Implements DL_GroupParameters< T >.

Definition at line 107 of file eccrypto.h.

◆ EncodeElement()

template<class EC >

void DL_GroupParameters_EC< EC >::EncodeElement	(	bool	reversible,
		const Element &	element,
		byte *	encoded ) const

inline

Definition at line 108 of file eccrypto.h.

◆ GetEncodedElementSize()

template<class EC >

virtual unsigned int DL_GroupParameters_EC< EC >::GetEncodedElementSize ( bool reversible ) const

inlinevirtual

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()

Implements DL_GroupParameters< T >.

Definition at line 115 of file eccrypto.h.

◆ DecodeElement()

template<class EC >

Element DL_GroupParameters_EC< EC >::DecodeElement	(	const byte *	encoded,
		bool	checkForGroupMembership ) const

inlinevirtual

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()

Implements DL_GroupParameters< T >.

Definition at line 122 of file eccrypto.h.

◆ GetMaxExponent()

template<class EC >

Integer DL_GroupParameters_EC< EC >::GetMaxExponent ( ) const

inlinevirtual

Retrieves the maximum exponent for the group.

Returns: the maximum exponent for the group

Implements DL_GroupParameters< T >.

Definition at line 132 of file eccrypto.h.

◆ IsIdentity()

template<class EC >

bool DL_GroupParameters_EC< EC >::IsIdentity ( const Element & element ) const

inline

Definition at line 133 of file eccrypto.h.

◆ StaticAlgorithmNamePrefix()

template<class EC >

static std::string DL_GroupParameters_EC< EC >::StaticAlgorithmNamePrefix ( )

inlinestatic

Definition at line 135 of file eccrypto.h.

◆ SetPointCompression()

template<class EC >

void DL_GroupParameters_EC< EC >::SetPointCompression ( bool compress )

inline

Definition at line 152 of file eccrypto.h.

◆ GetPointCompression()

template<class EC >

bool DL_GroupParameters_EC< EC >::GetPointCompression ( ) const

inline

Definition at line 153 of file eccrypto.h.

◆ SetEncodeAsOID()

template<class EC >

void DL_GroupParameters_EC< EC >::SetEncodeAsOID ( bool encodeAsOID )

inline

Definition at line 155 of file eccrypto.h.

◆ GetEncodeAsOID()

template<class EC >

bool DL_GroupParameters_EC< EC >::GetEncodeAsOID ( ) const

inline

Definition at line 156 of file eccrypto.h.

◆ GetCurve()

template<class EC >

const EllipticCurve & DL_GroupParameters_EC< EC >::GetCurve ( ) const

inline

Definition at line 158 of file eccrypto.h.

◆ operator==()

template<class EC >

bool DL_GroupParameters_EC< EC >::operator== ( const ThisClass & rhs ) const

inline

Definition at line 160 of file eccrypto.h.

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

eccrypto.h

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Typedef Documentation

◆ EllipticCurve

◆ Point

◆ Element

◆ DefaultCofactorOption

Constructor & Destructor Documentation

◆ ~DL_GroupParameters_EC()

◆ DL_GroupParameters_EC() [1/4]

◆ DL_GroupParameters_EC() [2/4]

◆ DL_GroupParameters_EC() [3/4]

◆ DL_GroupParameters_EC() [4/4]

Member Function Documentation

◆ Initialize() [1/2]

◆ Initialize() [2/2]

◆ GetVoidValue()

◆ AssignFrom()

◆ GenerateRandom()

◆ GetBasePrecomputation()

◆ AccessBasePrecomputation()

◆ GetSubgroupOrder()

◆ GetCofactor()

◆ ValidateGroup()

◆ FastSubgroupCheckAvailable()

◆ EncodeElement()

◆ GetEncodedElementSize()

◆ DecodeElement()

◆ GetMaxExponent()

◆ IsIdentity()

◆ StaticAlgorithmNamePrefix()

◆ SetPointCompression()

◆ GetPointCompression()

◆ SetEncodeAsOID()

◆ GetEncodeAsOID()

◆ GetCurve()

◆ operator==()