It appears that John Levine <[email protected]> said: >It appears that Paul Hoffman <[email protected]> said: >>Again, this discussion would be a lot easier if you described the threat >>model and showed that the model applies to >>all users of this specification. I suspect they reason you haven't is because >>there are plenty of users who don't >>meet the implied model. > >This draft is increasingly reminding me of the old joke about a ten >ton steel door on a cardboard box. > >While I realize there is at least one high value application, signing >SSL certificates, most of them are much much less valuable and need >correspondingly less security. You also need to keep in mind in the >threat model how easy it is to attack. Your bank card probably has a >four digit PIN because it is hard to make repeated guesses at at ATM >so four digits, about 10 bits, is enough. Similarly, I would think >that if you were rotating through DNS strings, trying one every five >seconds is about the fastest you can do, and of course any sensible >target would notice the attack and shut it down. > >Look at the ridiculous set of TXT records at stanford.edu and you'll >find 75 validation records with widely varying strings. One, from a >mailing company, has five base 36 characters, which is 180 bits.
Oops, 180 possible values, about 8 bits. Weak though it is, it is fine for this low value application. >I know people at that company, they're not stupid, that's plenty for >their application, checking that a customer uses the domain they say >they do. > >This draft desperately needs a threat model, so it can give reasonable >advice on what sort of token is appropriate for various applications. > >R's, >John > _______________________________________________ DNSOP mailing list -- [email protected] To unsubscribe send an email to [email protected]
