[1508] in cryptography@c2.net mail archive
Re: Access to Plaintext: An Obvious Consequence
daemon@ATHENA.MIT.EDU (Donald E. Eastlake 3rd)
Wed Sep 17 15:27:59 1997
Date: Wed, 17 Sep 1997 00:59:35 -0400 (EDT)
From: "Donald E. Eastlake 3rd" <dee@cybercash.com>
To: Robert Hettinga <rah@shipwright.com>
Cc: cryptography@c2.net
In-Reply-To: <v03110769b044bd788d52@[139.167.130.248]>
Generally modern systems encrypt with a random symmetric key and then send
that symmetric key encrypted under the public key of the recipient along with
the main encrypted message. All that would be necessary would be to in
addition provide the symmetric key encrypted under a government provided
public key (or public key for which the government had been provided the
private key). The intended recipient and the government would then each be
able to decrypt the symmetric key using their private key and read the
message. This is similar to the current Notes work factor scheme where Notes
can be shipped worldwide with 128 bit encryption but if it detects that it is
communicating with an international copy, it also encrypts 88 bits of the key
under a public key provided by NSA. Thus, to most people, the strength is
128 bits but to the US government and those who can get the cooperation of
the US government, the strength is only 40 bits.
Donald
On Tue, 16 Sep 1997, Robert Hettinga wrote:
> Date: Tue, 16 Sep 1997 18:49:44 -0400
> From: Robert Hettinga <rah@shipwright.com>
>
> --- begin forwarded text
>
> From: Somebody
> Date: Tue, 16 Sep 1997 10:12:47 -0400 (EDT)
> To: rah@shipwright.com
> Subject: Access to Plaintext: An Obvious Consequence
>
> Bob,
>
> If no encryption product can be sold that can't decrypt everything it
> encrypts, then
> no public key systems can come to market. That would effectively eliminate
> the entire range of encryption products of interest to you.
>
> Surely, this is clear?
>
> <Somebody's .sig>
>
> --- end forwarded text
> -----------------
> Robert Hettinga (rah@shipwright.com), Philodox
> e$, 44 Farquhar Street, Boston, MA 02131 USA
> "... however it may deserve respect for its usefulness and antiquity,
> [predicting the end of the world] has not been found agreeable to
> experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'
> The e$ Home Page: http://www.shipwright.com/
=====================================================================
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318 Acton Street +1 978-371-7148(fax) dee@world.std.com
Carlisle, MA 01741 USA +1 703-620-4200(main office, Reston, VA)
http://www.cybercash.com http://www.privacy.org/ipc
