/** Generates session key and mac key. Caller must synch on this. */
private void generateSessionKey() throws DHSessionKeyBuilder.InvalidPublicParameterException {
if (_sessionKey != null) return;
if (_keyBuilder == null)
throw new DHSessionKeyBuilder.InvalidPublicParameterException(
"Illegal state - never generated a key builder");
_keyBuilder.setPeerPublicValue(_receivedY);
_sessionKey = _keyBuilder.getSessionKey();
ByteArray extra = _keyBuilder.getExtraBytes();
_macKey = new SessionKey(new byte[SessionKey.KEYSIZE_BYTES]);
System.arraycopy(extra.getData(), 0, _macKey.getData(), 0, SessionKey.KEYSIZE_BYTES);
if (_log.shouldLog(Log.DEBUG))
_log.debug("Established outbound keys. cipher: " + _sessionKey + " mac: " + _macKey);
}
/** caller must synch - only call once */
private void prepareSessionRequest() {
_keyBuilder = _keyFactory.getBuilder();
_sentX = new byte[UDPPacketReader.SessionRequestReader.X_LENGTH];
byte X[] = _keyBuilder.getMyPublicValue().toByteArray();
if (X.length == 257) System.arraycopy(X, 1, _sentX, 0, _sentX.length);
else if (X.length == 256) System.arraycopy(X, 0, _sentX, 0, _sentX.length);
else System.arraycopy(X, 0, _sentX, _sentX.length - X.length, X.length);
}
