ECFieldF2m JDK 1.6)

Constructors

public ECFieldF2m (int m)

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 normal basis.
Parameters:
- m - with 2^m being the number of elements.
Throws:
- IllegalArgumentException - if m is not positive.

public ECFieldF2m (int m, BigInteger rp)

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

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

public ECFieldF2m (int m, int[] ks)

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

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 - with 2^m being the number of elements.
- ks - the order of the middle term(s) of the reduction polynomial. Contents of this array are copied to protect against subsequent modification.
Throws:
- NullPointerException - if ks is null.
- 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.

Methods

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public boolean equals (Object obj)

Compares this finite field for equality with the specified object.

Compares this finite field for equality with the
specified object.
Returns: true if obj is an instance of ECFieldF2m and both m and the reduction polynomial match, false otherwise.
Parameters:
- obj - the object to be compared.

public int getFieldSize () [Specified in ECField]

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

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

public int getM ()

Returns the value m of this characteristic 2 finite field.

Returns the value m of this characteristic
2 finite field.
Returns: m with 2^m being the number of elements.

public int getMidTermsOfReductionPolynomial ()

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.

public BigInteger getReductionPolynomial ()

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.

public int hashCode ()

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