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RE: What is SES? (Was Re: SPF does not break forwarding)

2004-05-20 16:31:11
From: Weldon Whipple
Sent: Thursday, May 20, 2004 11:17 AM



<...>

Would someone clue me in to the meaning of SES? (Actually, just telling me
the words that SES stand for would probably suffice. (Google would do the
rest--but a  URL somewhere would be even better!)

SES stands for Signed Envelope Sender.  It means putting a cryptographic
cookie in MAIL FROM: so that you can distinguish bogus bounce spam from
legitimate DSN's to messages that you originated.  Since the crypto cookie
is a SHA-1 HMAC created with a secret key, you can tell what you originated
from a forgery.  If the key is different for each user, an end recipient can
do a CBV and have your MTA verify that the return path address really
belongs to the person who sent the mail.  Other variations of SES permit
public key crypto verification so that a CBV is not needed.

--

Seth Goodman


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