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The following archive was created by hippie-mail 7.98617-22 on Thu May 27 1999 - 23:44:21
staym@accessdata.com
Wed, 7 Apr 1999 9:16:13 -0700
Geez, how many times do we have to go thru this?
>However, on p.21 of the Handbook by Menezes et al. one reads:
> 1.39 Definition. The Vernam Cipher is a stream cipher defined
> on the alphabet A = {0,1}. A binary message m_1,m_2,... m_t
> is operated on by a binary key string k_1,k_2,... k_t of the
> same length to produce a ciphertext string c_1,c_2,... c_t
> where
> c_i = m_i (+) k_i 1 <= i <= t
> If the key string is randomly chosen and never used again, the
> Vernam cipher is called a one-time system or a one-time pad.
THE KEY IS THE SAME LENGTH AS THE MESSAGE!!!, not some
pseudo-random stream generated from fewer key-bits. A Vernam
Cipher is a stream cipher, and a one-time-pad is a stream cipher, and
the Vernam Cipher is a one-time-pad, but a stream cipher is NOT
NECESSARILY A ONE-TIME-PAD ( == Vernam Cipher) UNLESS YOU
XOR YOUR MESSAGE WITH RANDOM BITS (and the only way
we know how to get those is from physical chaotic sources) THUS
MAKING THE RANDOM BITS A KEY THE SIZE OF YOUR MESSAGE!
Now _please_, let this thread die.
Mike Stay
Cryptographer / Programmer
AccessData Corp.
mailto:staym@accessdata.com
The following archive was created by hippie-mail 7.98617-22 on Thu May 27 1999 - 23:44:21