Thanks to Daniel Goldman and Kelvin Fichter for their comments. A lot has been said about the security of optimistic rollups. In many cases, the concerns about the ORU security properties stem from the lack of availability of literature that expands on the fundamental properties of ORUs. In this short piece, I attempt to tackle the concerns that I come across on a frequent basis when discussing the security properties of ORUs.1-of-N Honesty AssumptionOptimistic rollups are optimistic (duh!). ...