[14762] in cryptography@c2.net mail archive
Re: A-B-a-b encryption
daemon@ATHENA.MIT.EDU (Ian Grigg)
Sun Nov 16 19:33:51 2003
X-Original-To: cryptography@metzdowd.com
X-Original-To: cryptography@metzdowd.com
Date: Sun, 16 Nov 2003 12:14:43 -0500
From: Ian Grigg <iang@systemics.com>
Reply-To: iang@systemics.com
To: martin f krafft <madduck@madduck.net>
Cc: crypto list <cryptography@metzdowd.com>
martin f krafft wrote:
>
> it came up lately in a discussion, and I couldn't put a name to it:
> a means to use symmetric crypto without exchanging keys:
>
> - Alice encrypts M with key A and sends it to Bob
> - Bob encrypts A(M) with key B and sends it to Alice
> - Alice decrypts B(A(M)) with key A, leaving B(M), sends it to Bob
> - Bob decrypts B(M) with key B leaving him with M.
>
> Are there algorithms for this already? What's the scheme called?
> I searched Schneier (non-extensively) but couldn't find a reference.
Perhaps you want to try looking at the various blinding
algorithms by Chaum (and Wagner, also Brands). These use
schemes that are transitive (if that's the word).
iang
---------------------------------------------------------------------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to majordomo@metzdowd.com
