org.bouncycastle.math.ec

Class ECFieldElement.F2m

java.lang.Object

org.bouncycastle.math.ec.ECFieldElement

org.bouncycastle.math.ec.ECFieldElement.AbstractF2m

org.bouncycastle.math.ec.ECFieldElement.F2m

All Implemented Interfaces:

ECConstants

Enclosing class:

ECFieldElement

public static class ECFieldElement.F2m
extends ECFieldElement.AbstractF2m

Class representing the Elements of the finite field F 2 m in polynomial basis (PB) representation. Both trinomial (TPB) and pentanomial (PPB) polynomial basis representations are supported. Gaussian normal basis (GNB) representation is not supported.

Nested Class Summary

Nested classes/interfaces inherited from class org.bouncycastle.math.ec.ECFieldElement

ECFieldElement.AbstractF2m, ECFieldElement.AbstractFp, ECFieldElement.F2m, ECFieldElement.Fp

Field Summary

Fields

Modifier and Type	Field and Description
static int	GNB Indicates gaussian normal basis representation (GNB).
static int	PPB Indicates pentanomial basis representation (PPB).
static int	TPB Indicates trinomial basis representation (TPB).

Fields inherited from interface org.bouncycastle.math.ec.ECConstants

EIGHT, FOUR, ONE, THREE, TWO, ZERO

Constructor Summary

Constructors

Constructor and Description
F2m(int m, int k1, int k2, int k3, java.math.BigInteger x) Deprecated. Use ECCurve.fromBigInteger to construct field elements

Method Summary

Modifier and Type	Method and Description
ECFieldElement	add(ECFieldElement b)
ECFieldElement	addOne()
int	bitLength()
static void	checkFieldElements(ECFieldElement a, ECFieldElement b) Deprecated. Will be removed
ECFieldElement	divide(ECFieldElement b)
boolean	equals(java.lang.Object anObject)
java.lang.String	getFieldName()
int	getFieldSize()
int	getK1()
int	getK2()
int	getK3()
int	getM()
int	getRepresentation()
int	hashCode()
ECFieldElement	invert()
boolean	isOne()
boolean	isZero()
ECFieldElement	multiply(ECFieldElement b)
ECFieldElement	multiplyMinusProduct(ECFieldElement b, ECFieldElement x, ECFieldElement y)
ECFieldElement	multiplyPlusProduct(ECFieldElement b, ECFieldElement x, ECFieldElement y)
ECFieldElement	negate()
ECFieldElement	sqrt()
ECFieldElement	square()
ECFieldElement	squareMinusProduct(ECFieldElement x, ECFieldElement y)
ECFieldElement	squarePlusProduct(ECFieldElement x, ECFieldElement y)
ECFieldElement	squarePow(int pow)
ECFieldElement	subtract(ECFieldElement b)
boolean	testBitZero()
java.math.BigInteger	toBigInteger()

Methods inherited from class org.bouncycastle.math.ec.ECFieldElement.AbstractF2m

halfTrace, hasFastTrace, trace

Methods inherited from class org.bouncycastle.math.ec.ECFieldElement

getEncoded, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

GNB

public static final int GNB

Indicates gaussian normal basis representation (GNB). Number chosen according to X9.62. GNB is not implemented at present.

See Also:

Constant Field Values

TPB

public static final int TPB

Indicates trinomial basis representation (TPB). Number chosen according to X9.62.

See Also:

Constant Field Values

PPB

public static final int PPB

Indicates pentanomial basis representation (PPB). Number chosen according to X9.62.

See Also:

Constant Field Values

Constructor Detail

F2m

public F2m(int m,
           int k1,
           int k2,
           int k3,
           java.math.BigInteger x)

Deprecated. Use ECCurve.fromBigInteger to construct field elements

Constructor for PPB.

Parameters:

m - The exponent m of F 2 m.

k1 - The integer k1 where x m + x k3 + x k2 + x k1 + 1 represents the reduction polynomial f(z).

k2 - The integer k2 where x m + x k3 + x k2 + x k1 + 1 represents the reduction polynomial f(z).

k3 - The integer k3 where x m + x k3 + x k2 + x k1 + 1 represents the reduction polynomial f(z).

x - The BigInteger representing the value of the field element.

Method Detail

bitLength

public int bitLength()

Overrides:

bitLength in class ECFieldElement

isOne

public boolean isOne()

Overrides:

isOne in class ECFieldElement

isZero

public boolean isZero()

Overrides:

isZero in class ECFieldElement

testBitZero

public boolean testBitZero()

Overrides:

testBitZero in class ECFieldElement

toBigInteger

public java.math.BigInteger toBigInteger()

Specified by:

toBigInteger in class ECFieldElement

getFieldName

public java.lang.String getFieldName()

Specified by:

getFieldName in class ECFieldElement

getFieldSize

public int getFieldSize()

Specified by:

getFieldSize in class ECFieldElement

checkFieldElements

public static void checkFieldElements(ECFieldElement a,
                                      ECFieldElement b)

Deprecated. Will be removed

Checks, if the ECFieldElements a and b are elements of the same field F 2 m (having the same representation).

Parameters:

a - field element.

b - field element to be compared.

Throws:

java.lang.IllegalArgumentException - if a and b are not elements of the same field F 2 m (having the same representation).

add

public ECFieldElement add(ECFieldElement b)

Specified by:

add in class ECFieldElement

addOne

public ECFieldElement addOne()

Specified by:

addOne in class ECFieldElement

subtract

public ECFieldElement subtract(ECFieldElement b)

Specified by:

subtract in class ECFieldElement

multiply

public ECFieldElement multiply(ECFieldElement b)

Specified by:

multiply in class ECFieldElement

multiplyMinusProduct

public ECFieldElement multiplyMinusProduct(ECFieldElement b,
                                           ECFieldElement x,
                                           ECFieldElement y)

Overrides:

multiplyMinusProduct in class ECFieldElement

multiplyPlusProduct

public ECFieldElement multiplyPlusProduct(ECFieldElement b,
                                          ECFieldElement x,
                                          ECFieldElement y)

Overrides:

multiplyPlusProduct in class ECFieldElement

divide

public ECFieldElement divide(ECFieldElement b)

Specified by:

divide in class ECFieldElement

negate

public ECFieldElement negate()

Specified by:

negate in class ECFieldElement

square

public ECFieldElement square()

Specified by:

square in class ECFieldElement

squareMinusProduct

public ECFieldElement squareMinusProduct(ECFieldElement x,
                                         ECFieldElement y)

Overrides:

squareMinusProduct in class ECFieldElement

squarePlusProduct

public ECFieldElement squarePlusProduct(ECFieldElement x,
                                        ECFieldElement y)

Overrides:

squarePlusProduct in class ECFieldElement

squarePow

public ECFieldElement squarePow(int pow)

Overrides:

squarePow in class ECFieldElement

invert

public ECFieldElement invert()

Specified by:

invert in class ECFieldElement

sqrt

public ECFieldElement sqrt()

Specified by:

sqrt in class ECFieldElement

getRepresentation

public int getRepresentation()

Returns:

the representation of the field F 2 m, either of TPB (trinomial basis representation) or PPB (pentanomial basis representation).

getM

public int getM()

Returns:

the degree m of the reduction polynomial f(z).

getK1

public int getK1()

Returns:

TPB: The integer k where x m + x k + 1 represents the reduction polynomial f(z). PPB: The integer k1 where x m + x k3 + x k2 + x k1 + 1 represents the reduction polynomial f(z).

getK2

public int getK2()

Returns:

TPB: Always returns 0 PPB: The integer k2 where x m + x k3 + x k2 + x k1 + 1 represents the reduction polynomial f(z).

getK3

public int getK3()

Returns:

TPB: Always set to 0 PPB: The integer k3 where x m + x k3 + x k2 + x k1 + 1 represents the reduction polynomial f(z).

equals

public boolean equals(java.lang.Object anObject)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object