[3351] in cryptography@c2.net mail archive
RE: ArcotSign
daemon@ATHENA.MIT.EDU (William Whyte)
Wed Sep 23 12:17:12 1998
From: William Whyte <wwhyte@baltimore.ie>
To: "'Anonymous'" <nobody@replay.com>,
"cypherpunks@cyberpass.net"
<cypherpunks@cyberpass.net>,
"cryptography@c2.net"
<cryptography@c2.net>
Date: Wed, 23 Sep 1998 09:40:51 +0100
> For this to work, the public key has to be kept secret(!).
>...
> As Greg points out, much the same could be accomplished simply by having
> the servers share secret 3DES keys with their users, each user having his
> own private 3DES key. The users could encrypt messages using their 3DES
> key and the server would decrypt using the appropriate key, which would
> also serve to authenticate the user.
The difference between this scheme and a shared-secret scheme (if I
understand this scheme correctly) is that Arcot's infrastructure gives
you non-repudiation -- the central server can't forge authenticated
messages from you -- and so it's suitable for transactions of value
in a way that a shared-secret scheme isn't.
Cheers,
William
