Human ID through insecure channel

[Carl Ellison]

>Date: Mon, 16 Oct 1995 13:51:27 -0700
>From: Hal <hfinney at shell.portal.com>
>Subject: Human ID through insecure channel
>
>Here is an example of the Matsumoto/Imai scheme for identifying yourself
>via a shared secret over an insecure channel, a system which is simple
>enough to be done in your head but which can withstand repeated
>observations by an adversary without being broken.


Hal,

	has this been written up someplace where I might read their
description?

	From your description of it, I have a way to break it in O(N)
samples, where N is the number of characters in the challenge string and
the factor of proportionality is strictly a function of how sure you want
to be that you have a correct break.


 - Carl


 +--------------------------------------------------------------------------+
 |Carl M. Ellison      cme at tis.com    http://www.clark.net/pub/cme          |
 |Trusted Information Systems, Inc.   http://www.tis.com/                   |
 |3060 Washington Road          PGP 2.6.2:  61E2DE7FCB9D7984E9C8048BA63221A2|
 |Glenwood MD  21738         Tel:(301)854-6889      FAX:(301)854-5363       |
 +--------------------------------------------------------------------------+