Esempio n. 1
0
		private ChainKey getOrCreateChainKey(SessionState sessionState, ECPublicKey theirEphemeral)

		{
			try
			{
				if (sessionState.hasReceiverChain(theirEphemeral))
				{
					return sessionState.getReceiverChainKey(theirEphemeral);
				}
				else
				{
					RootKey rootKey = sessionState.getRootKey();
					ECKeyPair ourEphemeral = sessionState.getSenderRatchetKeyPair();
					Pair<RootKey, ChainKey> receiverChain = rootKey.createChain(theirEphemeral, ourEphemeral);
					ECKeyPair ourNewEphemeral = Curve.generateKeyPair();
					Pair<RootKey, ChainKey> senderChain = receiverChain.first().createChain(theirEphemeral, ourNewEphemeral);

					sessionState.setRootKey(senderChain.first());
					sessionState.addReceiverChain(theirEphemeral, receiverChain.second());
					sessionState.setPreviousCounter(Math.Max(sessionState.getSenderChainKey().getIndex() - 1, 0));
					sessionState.setSenderChain(ourNewEphemeral, senderChain.second());

					return receiverChain.second();
				}
			}
			catch (InvalidKeyException e)
			{
				throw new InvalidMessageException(e);
			}
		}