What does that mean? I asked one of the folks working on this to put it in layman's language:

We've determined how the POD and PDM verify the origin and destination of insulin delivery commands, which are protected with a "nonce," a semi-random number generated from the POD's lot number and serial number. Now we can generate our own insulin delivery commands, and thus have complete control of a POD, without the necessity of a PDM. We still have some basic detective work left to do, which is to analyze every command thoroughly, so that we have complete "coverage" of the protocol. There are a few commands which we have yet to fully reverse, but they should become clear to us in rather short order.

There's still plenty to do, and I'm hoping we'll have confirmation today of some other folks generating nonces. Keep the faith!