[Cryptography] Apple GovtOS/FBiOS & Proof of Work

[Henry Baker]

At 03:54 PM 3/19/2016, Jerry Leichter wrote:
>This discussion has gotten into all kinds of technologies, but it's not clear to me that the underlying properties achieved make much sense.  So let's go back and look at what we're trying to accomplish and why.
>
>Note that as given, this solution requires no cryptography at all!  It's ultimately the phone that has to enforce the property that only one update per interval will be treated as valid, and it can do that by simply remembering the time of the last update.

But the iPhone doesn't know *for sure* what time it is when it wakes up.  It's too easy to turn the clock back & do another update.

That's why Apple needs the equivalent of a block chain with a proof of work to prove to every iPhone (& each & every iPhone can check that proof) that a minimum amount of work has indeed been performed (& hence a minimum amount of time) since the previous update was computed.