[lkml]   [2011]   [Oct]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: status: establishing a PGP web of trust
    On Sat, 08 Oct 2011 01:02:13 EDT, Jon Masters said:

    > What I'm saying is that unless you sign something (random text, my
    > actual key(s)) in my presence, I can't actually know it was you I was
    > dealing with or someone else claiming to be you (or your identity).

    Now see, this is *exacltly* why security people have to be pedantic about
    stuff. What you originally asked for was "sign random data to demonstrate
    control of the key", and I pointed out that being able to sign a key was as
    good as being able to sign random data to prove control of the key.

    However, it now turns out that your *actual* worry is "binding the person
    who controls the key with the person who controls the e-mail", which is
    in fact a valid concern for some situations, and as pointed out, requires
    a bit more effort to establish.

    However, you have to remember that *all* real-life identity proofs are to
    some degree probabalistic. How do you know your lawyer is a *real* lawyer
    and not somebody with a fake degree? Mostly because the other lawers
    in town and the judges are convinced he's a lawyer too. Same goes for
    your doctor - how do you know he *really* went to med school? Even calling
    the med school and verifying only proves that somebody with that name went
    there that year. And yes, every year we hear about a few fake lawyers and
    doctors on the news. But society seems to muddle along just fine anyhow.

    (Incidentally, something most people don't realize is that the entire debit/credit
    card industry is *designed* with the assumption that between 2 and 4
    percent of all transactions will turn out to be fraudulent in some way. So
    everybody keeps a small buffer for chargebacks and life goes on).

    Similarly for PGP - it's not *that* hard to create a totally new e-mail
    account, a new name, get a fake ID, go to a few key signings, and have a nice
    validated bogus PGP ID. However, do we really *care* in that case? Probably
    not. What we *care* more about is somebody creating a fake ID in somebody
    else's name. And that turns out to be rather self-limiting - all it takes is
    *one* person to send the real person an e-mail that says "Glad to meet you at
    the keysigining last week", and the ruse is revealed when the real person
    realizes he wasn't *at* the keysigning.

    And even if the identities *are* perfectly confirmed, that doesn't remove all
    the risk. You can have somebody you've known for years, do background checks,
    and be 100% convinced he's the real person. But if you then use PGP to encrypt
    the secret plans for the revolution and e-mail it to him, PGP says nothing at
    all about whether he's in reality a government mole who's infiltrated your

    That's why nobody worries too much about the "is it really him?" side - the
    world is full enough of properly identified but duplicious people to worry
    about the few who have fake identities and are duplicious. ;)

    [unhandled content-type:application/pgp-signature]
     \ /
      Last update: 2011-10-08 16:41    [W:0.032 / U:1.892 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site