Class EllipticCurve
 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
Constructor  Description 

EllipticCurve(ECField field,
BigInteger a,
BigInteger b)  Creates an elliptic curve with the specified elliptic field 
EllipticCurve(ECField field,
BigInteger a,
BigInteger b,
byte[] seed)  Creates an elliptic curve with the specified elliptic field 
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 coefficient 
BigInteger  getB()  Returns the second coefficient 
ECField  getField()  Returns the finite field 
byte[]  getSeed()  Returns the seeding bytes 
int  hashCode()  Returns a hash code value for this elliptic curve. 
Methods declared in class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
EllipticCurve
public EllipticCurve(ECField field, BigInteger a, BigInteger b)
Creates an elliptic curve with the specified elliptic field field
and the coefficients a
and b
.
 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
public EllipticCurve(ECField field, BigInteger a, BigInteger b, byte[] seed)
Creates an elliptic curve with the specified elliptic field field
, the coefficients a
and b
, and the seed
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 Detail
getField
public ECField getField()
Returns the finite field field
that this elliptic curve is over.
 Returns:
 the field
field
that this curve is over.
getA
public BigInteger getA()
Returns the first coefficient a
of the elliptic curve.
 Returns:
 the first coefficient
a
.
getB
public BigInteger getB()
Returns the second coefficient b
of the elliptic curve.
 Returns:
 the second coefficient
b
.
getSeed
public byte[] getSeed()
Returns the seeding bytes seed
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
public boolean equals(Object obj)
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)