NPR : E-Mail Encryption Rare in Everyday Use

[Alex Alten]

At 05:58 AM 3/3/2006 +0000, Ben Laurie wrote:
>alex at alten.org wrote:
> >> alex at alten.org wrote:
> >>>> Alex Alten wrote:
> >>>>> At 05:12 PM 2/26/2006 +0000, Ben Laurie wrote:
> >>>>>> Alex Alten wrote:
> >>>>>>> At 02:59 PM 2/24/2006 +0000, Ben Laurie wrote:
> >>>>>>>> Ed Gerck wrote: We have keyservers for this (my chosen
> >>>>>>>> technology was PGP). If you liken their use to looking up an
> >>>>>>>> address in an address book, this isn't hard for users to grasp.
> >>>>>>>>
> >>>>>>> I used PGP (Enterprise edition?) to encrypt my work emails to
> >>>>>>> a distributed set of members last year.  We all had each
> >>>>>>> other's
> >>>>>>> public keys (about a dozen or so).
> >>>>>>>
> >>>>>>> What I really hated about it was that when fred at company.com sent
> >>>>>>> me an email often I couldn't decrypt it.  Why?  Because his
> >>>>>>> firm's email server decided to put in the FROM field
> >>>>>>> "fred at server.company.com". Since it didn't match the email name
> >>>>>>> in his X.509 certificate's DN it wouldn't decrypt the S/MIME
> >>>>>>> attachment. This also caused problems with replying to his email.
> >>>>>>> It took us hours, with several experimental emails sent back and
> >>>>>>> forth, to figure out the root of the problem.
> >>>>>>>
> >>>>>>> No wonder PKI has died commercially and encrypted email is on the
> >>>>>>>  endangered species list.
> >>>>>> I trust you don't think this is a problem with PKI, right? Since
> >>>>>> clearly the issue is with the s/w you were using.
> >>>>> I place the blame squarely on X.509 PKI.  The identity aspect of it
> >>>>> is all screwed up. No software implementation can overcome such a
> >>>>> fundamental architectural flaw.
> >>>> OK - I'll bite - why does the sender's identity have any impact on the
> >>>> recipient's ability to decrypt?
> >>>>
> >>> Because the software needs a unique ID/name to find the correct
> >>> key to use. In practice (corporate) users can have multiple email
> >>> names, see my reply to Peter Gutman.  This is not the fault of
> >>> the email architecture, which has been working fine for 30-40
> >>> years, but the fault
> >>> of the X.509 architecture trying to piggyback on an address/name
> >>> space that is not designed with security/cryptography
> >>> considerations in mind.
> >> I have to admit to not being familiar with S/MIME, but the usual
> >> practice is to identify the signing key in the signature. Certainly this
> >> is what OpenPGP does. Its also kinda weird to refuse to decrypt just
> >> because the signature can't be verified.
> >>
> >
> > How does OpenPGP identify the signing key in the incoming email's 
> signature?
>
>Here's the output of one of the example programs in OpenPGP:SDK
>(http://openpgp.nominet.org.uk/), showing the structure of an OpenPGP
>signed file. I trust it is self-explanatory.

Assuming this file is attached to an incoming email message, how does the
receiver's email software match the Signer ID (= 0x8337FE6485F4ED64) to
a X.509 cert in his local cache that is associated with the email sender's name
(= "fred at company.com")?


--

- Alex Alten


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