java.lang.Object
java.security.spec.EllipticCurve
public class EllipticCurve extends Object
This immutable class holds the necessary values needed to represent
an elliptic curve.
 Since:
 1.5
 See Also:
ECField
,ECFieldFp
,ECFieldF2m

Constructor Summary
Constructors Constructor Description EllipticCurve(ECField field, BigInteger a, BigInteger b)
Creates an elliptic curve with the specified elliptic fieldfield
and the coefficientsa
andb
.EllipticCurve(ECField field, BigInteger a, BigInteger b, byte[] seed)
Creates an elliptic curve with the specified elliptic fieldfield
, the coefficientsa
andb
, and theseed
used for curve generation. 
Method Summary
Modifier and Type Method Description boolean
equals(Object obj)
Compares this elliptic curve for equality with the specified object.BigInteger
getA()
Returns the first coefficienta
of the elliptic curve.BigInteger
getB()
Returns the second coefficientb
of the elliptic curve.ECField
getField()
Returns the finite fieldfield
that this elliptic curve is over.byte[]
getSeed()
Returns the seeding bytesseed
used during curve generation.int
hashCode()
Returns a hash code value for this elliptic curve.

Constructor Details

EllipticCurve
Creates an elliptic curve with the specified elliptic fieldfield
and the coefficientsa
andb
. Parameters:
field
 the finite field that this elliptic curve is over.a
 the first coefficient of this elliptic curve.b
 the second coefficient of this elliptic curve. Throws:
NullPointerException
 iffield
,a
, orb
is null.IllegalArgumentException
 ifa
orb
is not null and not infield
.

EllipticCurve
Creates an elliptic curve with the specified elliptic fieldfield
, the coefficientsa
andb
, and theseed
used for curve generation. Parameters:
field
 the finite field that this elliptic curve is over.a
 the first coefficient of this elliptic curve.b
 the second coefficient of this elliptic curve.seed
 the bytes used during curve generation for later validation. Contents of this array are copied to protect against subsequent modification. Throws:
NullPointerException
 iffield
,a
, orb
is null.IllegalArgumentException
 ifa
orb
is not null and not infield
.


Method Details

getField
Returns the finite fieldfield
that this elliptic curve is over. Returns:
 the field
field
that this curve is over.

getA
Returns the first coefficienta
of the elliptic curve. Returns:
 the first coefficient
a
.

getB
Returns the second coefficientb
of the elliptic curve. Returns:
 the second coefficient
b
.

getSeed
public byte[] getSeed()Returns the seeding bytesseed
used during curve generation. May be null if not specified. Returns:
 the seeding bytes
seed
. A new array is returned each time this method is called.

equals
Compares this elliptic curve for equality with the specified object. Overrides:
equals
in classObject
 Parameters:
obj
 the object to be compared. Returns:
 true if
obj
is an instance of EllipticCurve and the field, A, and B match, false otherwise.  See Also:
Object.hashCode()
,HashMap

hashCode
public int hashCode()Returns a hash code value for this elliptic curve. Overrides:
hashCode
in classObject
 Returns:
 a hash code value computed from the hash codes of the field, A,
and B, as follows:
(field.hashCode() << 6) + (a.hashCode() << 4) + (b.hashCode() << 2)
 See Also:
Object.equals(java.lang.Object)
,System.identityHashCode(java.lang.Object)
