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Java™ Platform Standard Ed. 6 |
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java.lang.Object java.security.spec.ECFieldF2m
public class ECFieldF2m
This immutable class defines an elliptic curve (EC) characteristic 2 finite field.
ECField
Constructor Summary | |
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ECFieldF2m(int m)
Creates an elliptic curve characteristic 2 finite field which has 2^ m elements with normal basis. |
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ECFieldF2m(int m,
BigInteger rp)
Creates an elliptic curve characteristic 2 finite field which has 2^ m elements with
polynomial basis. |
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ECFieldF2m(int m,
int[] ks)
Creates an elliptic curve characteristic 2 finite field which has 2^ m elements with
polynomial basis. |
Method Summary | |
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boolean |
equals(Object obj)
Compares this finite field for equality with the specified object. |
int |
getFieldSize()
Returns the field size in bits which is m
for this characteristic 2 finite field. |
int |
getM()
Returns the value m of this characteristic
2 finite field. |
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. |
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. |
int |
hashCode()
Returns a hash code value for this characteristic 2 finite field. |
Methods inherited from class java.lang.Object |
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clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public ECFieldF2m(int m)
m
elements with normal basis.
m
- with 2^m
being the number of elements.
IllegalArgumentException
- if m
is not positive.public ECFieldF2m(int m, BigInteger rp)
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).
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.
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)
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.
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.
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.Method Detail |
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public int getFieldSize()
m
for this characteristic 2 finite field.
getFieldSize
in interface ECField
public int getM()
m
of this characteristic
2 finite field.
m
with 2^m
being the
number of elements.public BigInteger getReductionPolynomial()
public int[] getMidTermsOfReductionPolynomial()
public boolean equals(Object obj)
equals
in class Object
obj
- the object to be compared.
obj
is an instance
of ECFieldF2m and both m
and the reduction
polynomial match, false otherwise.Object.hashCode()
,
Hashtable
public int hashCode()
hashCode
in class Object
Object.equals(java.lang.Object)
,
Hashtable
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Java™ Platform Standard Ed. 6 |
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