de.flexiprovider.ec.keys
Class ECPublicKeySpec

java.lang.Object
  |
  +--de.flexiprovider.ec.keys.ECPublicKeySpec

All Implemented Interfaces:

KeySpec, java.security.spec.KeySpec

public final class ECPublicKeySpec

extends java.lang.Object

implements KeySpec

This class specifies a EC public key with its associated parameters.

Author:

Birgit Henhapl, Michele Boivin

See Also:

KeySpec, KeyFactory, X509EncodedKeySpec, ECPrivateKeySpec, Point, CurveParams

Constructor Summary

ECPublicKeySpec(byte[] encodedW, CurveParams params)
Generate an EC key specification based on an encoded point and optionally the parameters of the curve.

ECPublicKeySpec(ECPublicKeySpec other)
Copy constructor.

ECPublicKeySpec(Point W, CurveParams params)
Constructs a new public key specification.

Method Summary

byte[]	getEncodedW()
CurveParams	getParams()
Point	getW() Returns the public key W.
void	setParams(CurveParams params) Set the EC domain parameters for this public key.

Methods inherited from class java.lang.Object

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

Constructor Detail

ECPublicKeySpec

public ECPublicKeySpec(Point W,
                       CurveParams params)
                throws InvalidParameterException

Constructs a new public key specification. The parameters are the public key W and an EC domain parameters specification params (see ECParameterSpec).

Parameters:

W - public key represented by a Point

params - ECParameterSpec, characteristic of underlying field

Throws:

InvalidParameterException - if params == null or params does not match parameters specified by W.

ECPublicKeySpec

public ECPublicKeySpec(byte[] encodedW,
                       CurveParams params)
                throws InvalidParameterSpecException

Generate an EC key specification based on an encoded point and optionally the parameters of the curve. If curve parameters are presented, the point is decoded (which may lead to the Exceptions named below). Otherwise, the point is internally represented as byte array. Uncompressed encoding must be chosen for the point.

Parameters:

encodedW - the point in its uncompressed encoding

params - EC domain parameters

Throws:

InvalidParameterSpecException - if the point cannot be decoded with the given parameters.

ECPublicKeySpec

public ECPublicKeySpec(ECPublicKeySpec other)

Copy constructor.

Parameters:

other - another ECPublicKeySpec

Method Detail

getW

public Point getW()
           throws InvalidKeySpecException

Returns the public key W. W = sG, s is private key, G generator of the subgroup.

Returns:

the public key W

Throws:

InvalidKeySpecException - if no EC domain parameters have been defined for this public key yet.

See Also:

Point

getEncodedW

public byte[] getEncodedW()

Returns:

the public key in its uncompressed encoding

getParams

public CurveParams getParams()

Returns:

the EC domain parameters

setParams

public void setParams(CurveParams params)
               throws InvalidParameterSpecException

Set the EC domain parameters for this public key.

Parameters:

params - the domain parameters

Throws:

InvalidParameterSpecException - if the domain parameters are already set and params is not equal to the set parameters or if the encoded point cannot be decoded with the given parameters.