java.security.spec

Class ECFieldF2m

java.lang.Object

java.security.spec.ECFieldF2m

All Implemented Interfaces:

ECField

public class ECFieldF2m
extends Object
implements ECField

The parameters specifying a characteristic 2 finite field of an elliptic curve.

Constructor Summary

Constructors

Constructor and Description
ECFieldF2m(int m) Creates a new ECFieldF2m with 2^m elements with a normal basis.
ECFieldF2m(int m, BigInteger rp) Creates a new ECFieldF2m with 2^m elements with a polynomial basis and the reduction polynomial based on rp.
ECFieldF2m(int m, int[] ks) Creates a new ECFieldF2m with 2^m elements with a polynomial basis and the reduction polynomial based on ks.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj) Returns whether the specified object equals to this finite field.
int	getFieldSize() Returns the size of this finite field (in bits).
int	getM() Returns the exponent m for this finite field, with 2^m as the number of elements.
int[]	getMidTermsOfReductionPolynomial() Returns a copy of the integer array containing the order of the middle term(s) of the reduction polynomial for a polynomial basis.
BigInteger	getReductionPolynomial() Returns the base of the reduction polynomial with the n-th bit corresponding to the n-th coefficient of the reduction polynomial for a polynomial basis.
int	hashCode() Returns the hashcode value for this finite field.

Methods inherited from class java.lang.Object

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

Constructor Detail

ECFieldF2m

public ECFieldF2m(int m)

Creates a new ECFieldF2m with 2^m elements with a normal basis.

Parameters:

m - the exponent m for the number of elements.

Throws:

IllegalArgumentException - if m <= zero.

ECFieldF2m

public ECFieldF2m(int m,
                  BigInteger rp)

Creates a new ECFieldF2m with 2^m elements with a polynomial basis and the reduction polynomial based on rp.

The reduction polynomial must be either trinomial or pentanomial.

Parameters:

m - the exponent m for the number of elements.

rp - the base of the reduction polynomial with the n-th bit corresponding to the n-th coefficient of the reduction polynomial.

Throws:

IllegalArgumentException - if m <= zero or the rp is invalid.

ECFieldF2m

public ECFieldF2m(int m,
                  int[] ks)

Creates a new ECFieldF2m with 2^m elements with a polynomial basis and the reduction polynomial based on ks.

The reduction polynomial must be either trinomial or pentanomial.

Parameters:

m - the exponent m for the number of elements.

ks - the base of the reduction polynomial with coefficients given in descending order.

Throws:

IllegalArgumentException - if m <= zero or the reduction polynomial is not valid.

Method Detail

equals

public boolean equals(Object obj)

Returns whether the specified object equals to this finite field.

Overrides:

equals in class Object

Parameters:

obj - the object to compare to this finite field.

Returns:

true if the specified object is equal to this finite field, otherwise false.

See Also:

Object.hashCode()

getFieldSize

public int getFieldSize()

Returns the size of this finite field (in bits).

Specified by:

getFieldSize in interface ECField

Returns:

the size of this finite field (in bits).

getM

public int getM()

Returns the exponent m for this finite field, with 2^m as the number of elements.

Returns:

the exponent m for this finite field

getMidTermsOfReductionPolynomial

public int[] getMidTermsOfReductionPolynomial()

Returns a copy of the integer array containing the order of the middle term(s) of the reduction polynomial for a polynomial basis.

Returns:

a copy of the integer array containing the order of the middle term(s) of the reduction polynomial for a polynomial basis or null for a normal basis.

getReductionPolynomial

public BigInteger getReductionPolynomial()

Returns the base of the reduction polynomial with the n-th bit corresponding to the n-th coefficient of the reduction polynomial for a polynomial basis.

Returns:

the base of the reduction polynomial with the n-th bit corresponding to the n-th coefficient of the reduction polynomial for a polynomial basis or null for a normal basis.

hashCode

public int hashCode()

Returns the hashcode value for this finite field.

Overrides:

hashCode in class Object

Returns:

the hashcode value for this finite field.

See Also:

Object.equals(java.lang.Object)