/**
* To save from Attacks on Parameter Authentication one can send hash of parameters to other party
*
* @return byte[] of what???
*/
@Override
public byte[] getParametersHash() {
byte[] parms = NativeLib.getECParameters(ecGroup);
SHA1 sha1 = new SHA1(BLOCK_SIZE);
sha1.update(parms, 0, parms.length);
sha1.generate();
byte[] digest = sha1.getDigest();
return digest;
}
@Override
public boolean checkParametersHash(byte[] hash) {
if (hash == null || hash.length != BLOCK_SIZE) return false;
byte[] parms = NativeLib.getECParameters(ecGroup);
SHA1 sha1 = new SHA1(BLOCK_SIZE);
sha1.update(parms, 0, parms.length);
sha1.generate();
byte[] digest = sha1.getDigest();
for (int i = 0; i < digest.length; i++) if (digest[i] != hash[i]) return false;
return true;
}
@Override
public byte[] getSharedKey(byte[] composite) {
byte[] sharedKey;
sharedKey = NativeLib.getECSharedKey(privateKey, composite, ecGroup);
return sharedKey;
}
protected EllipticCurve(byte[] privateKey, int ecGroup) {
super(privateKey);
this.ecGroup = ecGroup;
publicKey = NativeLib.getECPublicKey(privateKey, ecGroup);
}