[10479] in cryptography@c2.net mail archive
Re: theory: unconditional security
daemon@ATHENA.MIT.EDU (Carl Ellison)
Tue Feb 19 14:06:08 2002
Message-Id: <3.0.5.32.20020219091841.01ce46d0@localhost>
Date: Tue, 19 Feb 2002 09:18:41 -0800
To: Greg Rose <ggr@qualcomm.com>
From: Carl Ellison <cme@acm.org>
Cc: Zefram <zefram@fysh.org>, cryptography@wasabisystems.com
In-Reply-To: <4.3.1.2.20020218113412.01d42910@127.0.0.1>
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At 11:38 AM 2/18/2002 +1100, Greg Rose wrote:
>At 10:15 PM 2/16/2002 +0000, Zefram wrote:
>>I've not been able to find any paper that describes the use of this
>>algorithm to give unconditional secrecy and integrity at once.
>>Nor have I found any paper describing doing this (as MAC or as
>>secrecy-plus-integrity) in GF(2^n), which makes it convenient to
>>operate on bit strings. This seems so stunningly useful that I'm
>>surprised it's not mentioned in AC.
>
>Like One-Time Pads, it seems stunningly useful only until you
>consider the practicalities. You still need key material as long as
>(in fact, twice as long as) the message, and you still cannot ever
>reuse the key material.
>
>>Can anyone point me at references that I'm missing?
>
>The sci.crypt FAQ has some material about why OTPs are useless in
>practice, and might have some references.
Greg,
OTPs were useless once. Modern tapes can hold quite a few bits. So
can a DVD-RAM disk, at 9.4GB. You can secure quite a few messages
with bits from one disk.
Zefram,
I suspect you find little written about OTP work because people have
always assumed the keys were impractical to distribute, store and
use.
- Carl
+------------------------------------------------------------------+
|Carl M. Ellison cme@acm.org http://world.std.com/~cme |
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+--Officer, officer, arrest that man. He's whistling a dirty song.-+
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