Optimistic ISM

Prioritizing safety over liveness
OptimisticISM is coming soon and is not yet implemented. This page is shown for informational purposes only. Details may change as the design matures.
The OptimisticISM encodes the optimistic verification security model pioneered by Optics and adopted by Synapse, Nomad, and Connext.
Much like the Multisig ISM, an OptimisticISM requires that m of n Validators have attested to the validity of a particular interchain message. However, unlike the Multisig ISM, messages do not get immediately delivered to their recipient. Instead, messages are not delivered until a fraud window has passed.
During the fraud window, any one of the watchers configured on the OptimisticISM have the opportunity to flag a message as fraudulent, preventing it from being delivered.
This security model prioritizes safety over liveness; only one watcher needs to be honest in order for the model to be safe. Dishonest watchers, however, can prevent valid messages from being delivered.