theory: unconditional security

[Carl Ellison]

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 at acm.org     http://world.std.com/~cme |
|    PGP: 08FF BA05 599B 49D2  23C6 6FFD 36BA D342                 |
+--Officer, officer, arrest that man. He's whistling a dirty song.-+

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