Jon Callas <j...@callas.org> writes: >You are of course correct, Peter, but are you saying that we shouldn't do >anything?
Well, I think it's necessary to consider the tradeoffs, if you don't know the other side's capabilities then it's a bit risky to assume that they're the same as yours. >You are wrong with this. > >*Messages* don't have this property, so long as they were encrypted to a >public key. It is unlocking the *key* that has this problem. The data was encrypted using pre-shared secrets (i.e. packet type 3) which does have this property. (Don't ask me, I didn't create the requirements, I just got called in to help diagnose the problem, which was that at some point S2K's coming from PGP Desktop were killing their embedded units. Maybe they were even using externally-generated private keys or who knows what rather than pre-shared secrets for messages, but whatever it was it was the S2K step that was causing it). >That problem *only* exists when you import a key from a fast client into a >slow client. That problem can be fixed either through some smart software >(look at the iteration count and if it's higher than you like, change it the >next time you use the key), or the user can do it manually. This doesn't work in a heterogeneous environment where the requirements will be something like messages having to comply with certain parts of the OpenPGP spec, and no more. Adding riders telling users how to manually configure individual applications doesn't work because end-users will never read the technical spec, or even know that it exists. I guess we could argue this point endlessly, but I really just brought it up to mention the unintended consequences of a particular design decision, and more generally the dangers of allowing unbounded integer and general data ranges in specs. Some implementations will enforce sensible limits, many won't (and will fail against fairly trivial attacks because of this), and without any guidance in the spec the ones that do take care to bound values are deemed non-compliant while the vulnerable ones that don't do any checking are deemed compliant. This is completely backwards for a security spec. Peter. --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majord...@metzdowd.com