private void initFromKey(Key key) throws InvalidKeyException {
if (agreement instanceof ECMQVBasicAgreement) {
if (!(key instanceof MQVPrivateKey)) {
throw new InvalidKeyException(
kaAlgorithm
+ " key agreement requires "
+ getSimpleName(MQVPrivateKey.class)
+ " for initialisation");
}
MQVPrivateKey mqvPrivKey = (MQVPrivateKey) key;
ECPrivateKeyParameters staticPrivKey =
(ECPrivateKeyParameters)
ECUtil.generatePrivateKeyParameter(mqvPrivKey.getStaticPrivateKey());
ECPrivateKeyParameters ephemPrivKey =
(ECPrivateKeyParameters)
ECUtil.generatePrivateKeyParameter(mqvPrivKey.getEphemeralPrivateKey());
ECPublicKeyParameters ephemPubKey = null;
if (mqvPrivKey.getEphemeralPublicKey() != null) {
ephemPubKey =
(ECPublicKeyParameters)
ECUtil.generatePublicKeyParameter(mqvPrivKey.getEphemeralPublicKey());
}
MQVPrivateParameters localParams =
new MQVPrivateParameters(staticPrivKey, ephemPrivKey, ephemPubKey);
this.parameters = staticPrivKey.getParameters();
// TODO Validate that all the keys are using the same parameters?
agreement.init(localParams);
} else {
if (!(key instanceof PrivateKey)) {
throw new InvalidKeyException(
kaAlgorithm
+ " key agreement requires "
+ getSimpleName(ECPrivateKey.class)
+ " for initialisation");
}
ECPrivateKeyParameters privKey =
(ECPrivateKeyParameters) ECUtil.generatePrivateKeyParameter((PrivateKey) key);
this.parameters = privKey.getParameters();
agreement.init(privKey);
}
}
public BigInteger calculateAgreement(CipherParameters pubKey) {
ECPublicKeyParameters pub = (ECPublicKeyParameters) pubKey;
ECPoint P = pub.getQ().multiply(key.getD());
// if (p.isInfinity()) throw new RuntimeException("d*Q == infinity");
return P.getX().toBigInteger();
}