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Android APIs
public class

ECFieldF2m

extends Object
implements ECField
java.lang.Object
   ↳ java.security.spec.ECFieldF2m

Class Overview

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

Summary

Public Constructors
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 .
Public Methods
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.
[Expand]
Inherited Methods
From class java.lang.Object
From interface java.security.spec.ECField

Public Constructors

public ECFieldF2m (int m)

Added in API level 1

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 .

public ECFieldF2m (int m, BigInteger rp)

Added in API level 1

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.

public ECFieldF2m (int m, int[] ks)

Added in API level 1

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.

Public Methods

public boolean equals ( Object obj)

Added in API level 1

Returns whether the specified object equals to this finite field.

Parameters
obj the object to compare to this finite field.
Returns
  • true if the specified object is equal to this finite field, otherwise false .

public int getFieldSize ()

Added in API level 1

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

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

public int getM ()

Added in API level 1

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

Returns
  • the exponent m for this finite field

public int[] getMidTermsOfReductionPolynomial ()

Added in API level 1

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.

public BigInteger getReductionPolynomial ()

Added in API level 1

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.

public int hashCode ()

Added in API level 1

Returns the hashcode value for this finite field.

Returns
  • the hashcode value for this finite field.