Added in API level 1

ECFieldF2m

open class ECFieldF2m : ECField
kotlin.Any
   ↳ java.security.spec.ECFieldF2m

This immutable class defines an elliptic curve (EC) characteristic 2 finite field.

Summary

Public constructors

Creates an elliptic curve characteristic 2 finite field which has 2^m elements with normal basis.

Creates an elliptic curve characteristic 2 finite field which has 2^m elements with polynomial basis.

ECFieldF2m(m: Int, ks: IntArray!)

Creates an elliptic curve characteristic 2 finite field which has 2^m elements with polynomial basis.

Public methods
open Boolean
equals(other: Any?)

Compares this finite field for equality with the specified object.

open Int

Returns the field size in bits which is m for this characteristic 2 finite field.

open Int

Returns the value m of this characteristic 2 finite field.

open IntArray!

Returns an integer array which contains the order of the middle term(s) of the reduction polynomial for polynomial basis or null for normal basis.

open BigInteger!

Returns a BigInteger whose i-th bit corresponds to the i-th coefficient of the reduction polynomial for polynomial basis or null for normal basis.

open Int

Returns a hash code value for this characteristic 2 finite field.

Public constructors

ECFieldF2m

Added in API level 1
ECFieldF2m(m: Int)

Creates an elliptic curve characteristic 2 finite field which has 2^m elements with normal basis.

Parameters
m Int: with 2^m being the number of elements.
Exceptions
java.lang.IllegalArgumentException if m is not positive.

ECFieldF2m

Added in API level 1
ECFieldF2m(
    m: Int,
    rp: BigInteger!)

Creates an elliptic curve characteristic 2 finite field which has 2^m elements with polynomial basis. The reduction polynomial for this field is based on rp whose i-th bit corresponds to the i-th coefficient of the reduction polynomial.

Note: A valid reduction polynomial is either a trinomial (X^m + X^k + 1 with m > k >= 1) or a pentanomial (X^m + X^k3 + X^k2 + X^k1 + 1 with m > k3 > k2 > k1 >= 1).

Parameters
m Int: with 2^m being the number of elements.
rp BigInteger!: the BigInteger whose i-th bit corresponds to the i-th coefficient of the reduction polynomial.
Exceptions
java.lang.NullPointerException if rp is null.
java.lang.IllegalArgumentException if m is not positive, or rp does not represent a valid reduction polynomial.

ECFieldF2m

Added in API level 1
ECFieldF2m(
    m: Int,
    ks: IntArray!)

Creates an elliptic curve characteristic 2 finite field which has 2^m elements with polynomial basis. The reduction polynomial for this field is based on ks whose content contains the order of the middle term(s) of the reduction polynomial. Note: A valid reduction polynomial is either a trinomial (X^m + X^k + 1 with m > k >= 1) or a pentanomial (X^m + X^k3 + X^k2 + X^k1 + 1 with m > k3 > k2 > k1 >= 1), so ks should have length 1 or 3.

Parameters
m Int: with 2^m being the number of elements.
ks IntArray!: the order of the middle term(s) of the reduction polynomial. Contents of this array are copied to protect against subsequent modification.
Exceptions
java.lang.NullPointerException if ks is null.
java.lang.IllegalArgumentException ifm is not positive, or the length of ks is neither 1 nor 3, or values in ks are not between m-1 and 1 (inclusive) and in descending order.

Public methods

equals

Added in API level 1
open fun equals(other: Any?): Boolean

Compares this finite field for equality with the specified object.

Parameters
obj the object to be compared.
Return
Boolean true if obj is an instance of ECFieldF2m and both m and the reduction polynomial match, false otherwise.

getFieldSize

Added in API level 1
open fun getFieldSize(): Int

Returns the field size in bits which is m for this characteristic 2 finite field.

Return
Int the field size in bits.

getM

Added in API level 1
open fun getM(): Int

Returns the value m of this characteristic 2 finite field.

Return
Int m with 2^m being the number of elements.

getMidTermsOfReductionPolynomial

Added in API level 1
open fun getMidTermsOfReductionPolynomial(): IntArray!

Returns an integer array which contains the order of the middle term(s) of the reduction polynomial for polynomial basis or null for normal basis.

Return
IntArray! an integer array which contains the order of the middle term(s) of the reduction polynomial for polynomial basis or null for normal basis. A new array is returned each time this method is called.

getReductionPolynomial

Added in API level 1
open fun getReductionPolynomial(): BigInteger!

Returns a BigInteger whose i-th bit corresponds to the i-th coefficient of the reduction polynomial for polynomial basis or null for normal basis.

Return
BigInteger! a BigInteger whose i-th bit corresponds to the i-th coefficient of the reduction polynomial for polynomial basis or null for normal basis.

hashCode

Added in API level 1
open fun hashCode(): Int

Returns a hash code value for this characteristic 2 finite field.

Return
Int a hash code value.