-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

When we looked, at work, at the mechanisms by which sensitive e-mail
was leaked, we found that the biggest problem was misdirection of
e-mail, not eavesdropping.

To secure against this worst problem, we found that PGP had an
advantage over S/MIME, because S/MIME calls for the transmission of a
certificate chain with any signed message while PGP called for
certificates to be in the local keyring before you received a
message.  The problem is that there are too many people in the world
to allow name comparisons to mean anything.  So, the only security
comes from whether there is a certificate available or not.  As long
as the only certificates you have on hand are:

1.      verified personally by hand (not by some CA)

2.      only for those you know personally

you have a chance of security.  If, instead, you accept incoming
certificates, you are accepting certificates from the attacker,
chosen by the attacker to fool you into acting some way you shouldn't
(like send back some classified document).  If you encrypt either in
reply to an incoming message or via a certificate found from some
server, then you will be encrypting but sending the mail to an
improperly selected/verified party.

It turns out you can do even better if you label personally held
certificates (that you've verified personally) by project or group,
so that you can mark some e-mail as being intended for a particular
interest group, not for just any of the people whose certificates you
happen to hold.

It would also be very good if the e-mail agent would have PGP support
built in alongside S/MIME, sine PGP users outnumber S/MIME users.

 - Carl

- -- 

+------------------------------------------------------------------+
|Carl M. Ellison         [EMAIL PROTECTED]     http://world.std.com/~cme |
|    PGP: 08FF BA05 599B 49D2  23C6 6FFD 36BA D342                 |
+--Officer, officer, arrest that man. He's whistling a dirty song.-+

-----BEGIN PGP SIGNATURE-----
Version: PGP 6.5.8

iQA/AwUBO+FpDnPxfjyW5ytxEQJtxgCg0gXWdbIjg6Lh8ee6ljH+FPsoTtkAoM2I
71F387pxU6fd8rKDdHvQ8ld4
=/GiC
-----END PGP SIGNATURE-----

Reply via email to