Java compact1, compact2, compact3 java.security.spec Class EllipticCurve（JDK8）

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 - 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 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 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)