EllipticCurve

AI-generated Key Takeaways

• EllipticCurve is an immutable class representing an elliptic curve with its field and coefficients.

• It provides constructors to create curves with specified field, coefficients, and optional seed for generation.

• Methods allow access to the curve's field, coefficients, and seed, along with equality comparison and hash code generation.

• This class is fundamental for elliptic curve cryptography operations in Java security.

• See ECField, ECFieldFp, and ECFieldF2m for related field types.

public class EllipticCurve extends Object

This immutable class holds the necessary values needed to represent an elliptic curve.

See Also

• ECField
• ECFieldFp
• ECFieldF2m

Public Constructor Summary

	EllipticCurve(ECField field, BigInteger a, BigInteger b) Creates an elliptic curve with the specified elliptic field field and the coefficients a and b.
	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.

Public Method Summary

boolean	equals(Object obj) Compares this elliptic curve for equality with the specified object.
BigInteger	getA() Returns the first coefficient a of the elliptic curve.
BigInteger	getB() Returns the second coefficient b of the elliptic curve.
ECField	getField() Returns the finite field field that this elliptic curve is over.
byte[]	getSeed() Returns the seeding bytes seed used during curve generation.
int	hashCode() Returns a hash code value for this elliptic curve.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

Public Constructors

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	if field, a, or b is null.
IllegalArgumentException	if a or b is not null and not in field.

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	if field, a, or b is null.
IllegalArgumentException	if a or b is not null and not in field.

Public Methods

public boolean equals (Object obj)

Compares this elliptic curve for equality with the specified object.

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.

public BigInteger getA ()

Returns the first coefficient a of the elliptic curve.

Returns

• the first coefficient a.

public BigInteger getB ()

Returns the second coefficient b of the elliptic curve.

Returns

• the second coefficient b.

public ECField getField ()

Returns the finite field field that this elliptic curve is over.

Returns

• the field field that this curve is over.

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.

public int hashCode ()

Returns a hash code value for this elliptic curve.

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)