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From: bhayes@glacier.UUCP
Newsgroups: net.crypt
Subject: Re: One time pads
Message-ID: <6539@glacier.ARPA>
Date: Sun, 20-Apr-86 20:26:42 EST
Article-I.D.: glacier.6539
Posted: Sun Apr 20 20:26:42 1986
Date-Received: Wed, 23-Apr-86 11:58:17 EST
References: <484@ucsfcca.UUCP>
Reply-To: bhayes@glacier.UUCP (Barry Hayes)
Organization: Stanford University, IC Laboratory
Lines: 19
Keywords: one time pad, CD ROMs

In article <484@ucsfcca.UUCP> dick@ucsfcca.UUCP (Dick Karpinski) writes:
>The simplest encryption which is secure is the one time pad, right?
>[...] [Can you construct a] one time pad [by] selecting larger supplies
>of bits from one or several CD ROMs or simply compact disks of music?

There is a code known as a "book code" that does just this.  Choose a 
particular edition of a particular book and give a copy to each person
who is to use the code.  To find a key, agree to some character in the book
[e.g. by page/line/character triplet] and use the characters in the book
starting at that place.  The choice can be be by open communication
["page 25/line 16/character 12"] or more subtle methods [e.g. a function
of the California lottery winners for the day].  In general you can
leave the problem of key publication/distribution to other people by
agreeing to use, say, the editorial page of the Herald Tribune as a 
key.

Using CDs to distribute the keys is a nice high-tech gloss on an old
idea.
 -Barry