Quote from: Mike Hearn on July 11, 2013, 12:03:22 PM

Quote from: thanke on July 10, 2013, 09:11:32 PM

If the protocol breaks (is interrupted) after the server has signed and returned the refund transaction (T2) to the client, the server has to blacklist its input (the hash of T1) indefinitely, or am I overlooking something? Otherwise the client can replay T1 at a later time, after the locktime of T2 has passed, and refund to himself before the protocol is terminated. At least the server has to keep track of the timelock used in T2. What does the implementation do?

The server generates a new key each you open a channel and requires it be used. So you cannot replay T1 like that. When you present it to the server in order to open up the new channel it will notice it's using the wrong key.

Ok, so you mean the rejection of such a replay happens in step 6 of the wiki description, after the server has seen T1 completely (not only it's hash) and when the server doesn't find his freshly generated key in there?