Re: random number code.

Enzo Michelangeli (em@who.net)
Sat, 22 Aug 1998 08:04:38 +0800

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-----Original Message-----
From: Frank (Giff) Gifford <giff@eng.us.uu.net>
To: steven.soroka@mts.mb.ca <steven.soroka@mts.mb.ca>
Cc: CodherPlunks@toad.com <CodherPlunks@toad.com>
Date: Saturday, August 22, 1998 7:50 AM
Subject: Re: random number code.

[...]
>That's because you, as a human, look for patterns. When a pattern is
>found, you say, "Hey, this doesn't look right". It should be fine as-is.
>BUT! I wouldn't use THIS particular stream as source for a OTP, since you
>have told us some of the contents!

I would not not use ANY generated sequence for a OTP, simply because a OTP
is supposed to be *randomly* generated. If you produce a long pseudo-random
sequence starting from a comparatively small key, and xor it with the
plaintext, you are using a simple type of stream cipher. In that case, the
entropy of the sequence is not greater than the number of bits of the key,
instead of being (to the best of everybody's knowledge) equal to the the
sequence's length.

Enzo

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