ECP Class Reference

Elliptic Curve over GF(p), where p is prime. More...

#include <ecp.h>

Inheritance diagram for ECP:

Public Types
typedef ModularArithmetic	Field
typedef Integer	FieldElement
typedef ECPPoint	Point
Public Types inherited from AbstractGroup< ECPPoint >
typedef ECPPoint	Element

Public Member Functions
	ECP ()
	Construct an ECP.
	ECP (const ECP &ecp, bool convertToMontgomeryRepresentation)
	Construct an ECP.
	ECP (const Integer &modulus, const FieldElement &a, const FieldElement &b)
	Construct an ECP.
	ECP (BufferedTransformation &bt)
	Construct an ECP from BER encoded parameters.
void	DEREncode (BufferedTransformation &bt) const
	DER Encode.
bool	Equal (const Point &P, const Point &Q) const
	Compare two points.
const Point &	Identity () const
	Provides the Identity element.
const Point &	Inverse (const Point &P) const
	Inverts the element in the group.
bool	InversionIsFast () const
	Determine if inversion is fast.
const Point &	Add (const Point &P, const Point &Q) const
	Adds elements in the group.
const Point &	Double (const Point &P) const
	Doubles an element in the group.
Point	ScalarMultiply (const Point &P, const Integer &k) const
	Performs a scalar multiplication.
Point	CascadeScalarMultiply (const Point &P, const Integer &k1, const Point &Q, const Integer &k2) const
	TODO.
void	SimultaneousMultiply (Point *results, const Point &base, const Integer *exponents, unsigned int exponentsCount) const
	Multiplies a base to multiple exponents in a group.
Point	Multiply (const Integer &k, const Point &P) const
Point	CascadeMultiply (const Integer &k1, const Point &P, const Integer &k2, const Point &Q) const
bool	ValidateParameters (RandomNumberGenerator &rng, unsigned int level=3) const
bool	VerifyPoint (const Point &P) const
	Verifies points on elliptic curve.
unsigned int	EncodedPointSize (bool compressed=false) const
	Determines encoded point size.
bool	DecodePoint (Point &P, BufferedTransformation &bt, size_t len) const
	Decodes an elliptic curve point.
bool	DecodePoint (Point &P, const byte *encodedPoint, size_t len) const
	Decodes an elliptic curve point.
void	EncodePoint (byte *encodedPoint, const Point &P, bool compressed) const
	Encodes an elliptic curve point.
void	EncodePoint (BufferedTransformation &bt, const Point &P, bool compressed) const
	Encodes an elliptic curve point.
Point	BERDecodePoint (BufferedTransformation &bt) const
	BER Decodes an elliptic curve point.
void	DEREncodePoint (BufferedTransformation &bt, const Point &P, bool compressed) const
	DER Encodes an elliptic curve point.
Integer	FieldSize () const
const Field &	GetField () const
const FieldElement &	GetA () const
const FieldElement &	GetB () const
bool	operator== (const ECP &rhs) const
Public Member Functions inherited from AbstractGroup< ECPPoint >
virtual const Element &	Subtract (const Element &a, const Element &b) const
	Subtracts elements in the group.
virtual Element &	Accumulate (Element &a, const Element &b) const
	TODO.
virtual Element &	Reduce (Element &a, const Element &b) const
	Reduces an element in the congruence class.

Detailed Description

Elliptic Curve over GF(p), where p is prime.

Definition at line 26 of file ecp.h.

Member Typedef Documentation

Field

typedef ModularArithmetic ECP::Field

Definition at line 29 of file ecp.h.

FieldElement

typedef Integer ECP::FieldElement

Definition at line 30 of file ecp.h.

Point

typedef ECPPoint ECP::Point

Definition at line 31 of file ecp.h.

Constructor & Destructor Documentation

~ECP()

virtual ECP::~ECP ( )

inlinevirtual

Definition at line 33 of file ecp.h.

ECP() [1/4]

ECP::ECP ( )

inline

Construct an ECP.

Definition at line 36 of file ecp.h.

ECP() [2/4]

ECP::ECP	(	const ECP &	ecp,
		bool	convertToMontgomeryRepresentation )

Construct an ECP.

Parameters

ecp	the other ECP object
convertToMontgomeryRepresentation	flag indicating if the curve should be converted to a MontgomeryRepresentation.

Prior to Crypto++ 8.3 the default value for convertToMontgomeryRepresentation was false. it was changed due to two audit tools finding, "Signature-compatible with a copy constructor".

See also

ModularArithmetic, MontgomeryRepresentation

ECP() [3/4]

ECP::ECP ( const Integer & modulus, const FieldElement & a, const FieldElement & b )

inline

Construct an ECP.

Parameters

modulus	the prime modulus
a	Field::Element
b	Field::Element

Definition at line 52 of file ecp.h.

ECP() [4/4]

ECP::ECP

(

BufferedTransformation &

bt

)

Construct an ECP from BER encoded parameters.

Parameters

bt	BufferedTransformation derived object

This constructor will decode and extract the fields fieldID and curve of the sequence ECParameters

Member Function Documentation

DEREncode()

void ECP::DEREncode

(

BufferedTransformation &

bt

)

const

DER Encode.

Parameters

bt	BufferedTransformation derived object

DEREncode encode the fields fieldID and curve of the sequence ECParameters

Equal()

bool ECP::Equal ( const Point & P, const Point & Q ) const

virtual

Compare two points.

Parameters

P	the first point
Q	the second point

Returns

true if equal, false otherwise

Implements AbstractGroup< ECPPoint >.

Identity()

const Point & ECP::Identity ( ) const

virtual

Provides the Identity element.

Returns

the Identity element

Implements AbstractGroup< ECPPoint >.

Inverse()

const Point & ECP::Inverse ( const Point & a ) const

virtual

Inverts the element in the group.

Parameters

a	first element

Returns

the inverse of the element

Implements AbstractGroup< ECPPoint >.

InversionIsFast()

bool ECP::InversionIsFast ( ) const

inlinevirtual

Determine if inversion is fast.

Returns

true if inversion is fast, false otherwise

Reimplemented from AbstractGroup< ECPPoint >.

Definition at line 75 of file ecp.h.

Add()

const Point & ECP::Add ( const Point & a, const Point & b ) const

virtual

Adds elements in the group.

Parameters

a	first element
b	second element

Returns

the sum of a and b

Implements AbstractGroup< ECPPoint >.

Double()

const Point & ECP::Double ( const Point & a ) const

virtual

Doubles an element in the group.

Parameters

a	the element

Returns

the element doubled

Reimplemented from AbstractGroup< ECPPoint >.

ScalarMultiply()

Point ECP::ScalarMultiply ( const Point & a, const Integer & e ) const

virtual

Performs a scalar multiplication.

Parameters

a	multiplicand
e	multiplier

Returns

the product

Reimplemented from AbstractGroup< ECPPoint >.

CascadeScalarMultiply()

Point ECP::CascadeScalarMultiply ( const Point & x, const Integer & e1, const Point & y, const Integer & e2 ) const

virtual

TODO.

Parameters

x	first multiplicand
e1	the first multiplier
y	second multiplicand
e2	the second multiplier

Returns

TODO

Reimplemented from AbstractGroup< ECPPoint >.

SimultaneousMultiply()

void ECP::SimultaneousMultiply ( Point * results, const Point & base, const Integer * exponents, unsigned int exponentsCount ) const

virtual

Multiplies a base to multiple exponents in a group.

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

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

SimultaneousMultiply() must be implemented in a derived class.

Precondition

COUNTOF(results) == exponentsCount

COUNTOF(exponents) == exponentsCount

Reimplemented from AbstractGroup< ECPPoint >.

Multiply()

Point ECP::Multiply ( const Integer & k, const Point & P ) const

inline

Definition at line 82 of file ecp.h.

CascadeMultiply()

Point ECP::CascadeMultiply ( const Integer & k1, const Point & P, const Integer & k2, const Point & Q ) const

inline

Definition at line 84 of file ecp.h.

VerifyPoint()

bool ECP::VerifyPoint ( const Point & P ) const

virtual

Verifies points on elliptic curve.

Parameters

P	point to verify

Returns

true if the point is valid, false otherwise

Implements EncodedPoint< ECPPoint >.

EncodedPointSize()

unsigned int ECP::EncodedPointSize ( bool compressed = false ) const

inlinevirtual

Determines encoded point size.

Parameters

compressed

flag indicating if the point is compressed

Returns

the minimum number of bytes required to encode the point

Implements EncodedPoint< ECPPoint >.

Definition at line 90 of file ecp.h.

DecodePoint() [1/2]

bool ECP::DecodePoint ( Point & P, BufferedTransformation & bt, size_t len ) const

virtual

Decodes an elliptic curve point.

Parameters

P	point which is decoded
bt	source BufferedTransformation
len	number of bytes to read from the BufferedTransformation

Returns

true if a point was decoded, false otherwise

Implements EncodedPoint< ECPPoint >.

DecodePoint() [2/2]

bool ECP::DecodePoint ( Point & P, const byte * encodedPoint, size_t len ) const

virtual

Decodes an elliptic curve point.

Parameters

P	point which is decoded
encodedPoint	byte array with the encoded point
len	the size of the array

Returns

true if a point was decoded, false otherwise

Implements EncodedPoint< ECPPoint >.

EncodePoint() [1/2]

void ECP::EncodePoint ( byte * encodedPoint, const Point & P, bool compressed ) const

virtual

Encodes an elliptic curve point.

Parameters

P	point which is decoded
encodedPoint	byte array for the encoded point
compressed	flag indicating if the point is compressed

encodedPoint must be at least EncodedPointSize() in length

Implements EncodedPoint< ECPPoint >.

EncodePoint() [2/2]

void ECP::EncodePoint ( BufferedTransformation & bt, const Point & P, bool compressed ) const

virtual

Encodes an elliptic curve point.

Parameters

bt	target BufferedTransformation
P	point which is encoded
compressed	flag indicating if the point is compressed

Implements EncodedPoint< ECPPoint >.

BERDecodePoint()

Point ECP::BERDecodePoint ( BufferedTransformation & bt ) const

virtual

BER Decodes an elliptic curve point.

Parameters

bt	source BufferedTransformation

Returns

the decoded elliptic curve point

Implements EncodedPoint< ECPPoint >.

DEREncodePoint()

void ECP::DEREncodePoint ( BufferedTransformation & bt, const Point & P, bool compressed ) const

virtual

DER Encodes an elliptic curve point.

Parameters

bt	target BufferedTransformation
P	point which is encoded
compressed	flag indicating if the point is compressed

Implements EncodedPoint< ECPPoint >.

FieldSize()

Integer ECP::FieldSize ( ) const

inline

Definition at line 101 of file ecp.h.

GetField()

const Field & ECP::GetField ( ) const

inline

Definition at line 102 of file ecp.h.

GetA()

const FieldElement & ECP::GetA ( ) const

inline

Definition at line 103 of file ecp.h.

GetB()

const FieldElement & ECP::GetB ( ) const

inline

Definition at line 104 of file ecp.h.

operator==()

bool ECP::operator== ( const ECP & rhs ) const

inline

Definition at line 106 of file ecp.h.

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

• ecp.h