Re: [9fans] Sources Gone?

[erik quanstrom <quanstro@quanstro.net>]

> to my mind, the biggest security vulnerability in venti
> is the ability to unconditionally enumerate an entire file tree given
> its root score. if the VtPointer data structures, or the
> scores within them, were encrypted somehow, maybe
> that vulnerability could be mitigated. scores would still
> be useful, but only in conjunction with a (salted) key.

i'm not sure i understand.  either you have the key (score)
and you can decrypt the whole cyphertext (read the file tree
below), or you don't.  assuming of course that scores are too
hard to guess.  so the solution is: don't give out the root score.

(ot: you could think of a venti tree as a keyring, but that's
just nutty.)

> of course, this would mean that pointer blocks would no longer
> be shared between file trees, but it's my suspicion that
> they don't use a significant percentage of overall storage.

is there any other way to end up with the same pointer block
than starting with the same data?  conversely if either
data anywhere "below" (forgive the imprecision), pointer
blocks will change all the way up to the root and the root
will not be shared.  i don't see how information could leak,
either.

am i missing something?

- erik