Achieving Stronger Termination Clause Samples

Achieving Stronger Termination. As we briefly discussed in 5.2, some parties may terminate an instance of a protocol in a rather indecisive way: although they have made a decision, they do not know that they can stop; instead, they will simply block, waiting forever for messages that will never arrive. It is not clear to what extent this is a serious problem, but anyway, it is easy to modify protocol ABBA so that parties not only decide, but terminate in a more decisive fashion. Namely, when a party ▇▇ decides b for TID in round r, it can combine the signature shares that it has on hand to construct an S-threshold signature on the message (main-vote, TID, r, b). It then sends this threshold signature to all parties and stops. Thus, Pi can effectively erase all data in its internal state relevant to TID, and ignore all future incoming messages relating to TID. Any other party that is waiting for some other message, but instead receives the above threshold signature, can also decide b for TID, send the this signature to all parties, and then stop. Note that without this modification, the threshold signatures on main-votes other than abstain are actually not used by the protocol, and could be deleted.