Module java.base
Package java.security.spec

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

    Constructors
    Constructor
    Description
    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.

  • 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 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.

    Methods declared in class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

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

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

  • Method Details

    • 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 class 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.
      See Also:
      Object.hashCode(), HashMap

    • hashCode

      public int hashCode()
      Returns a hash code value for this elliptic curve.
      Overrides:
      hashCode in class Object
      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)