Re: Fwd: [pkzip's prng]

jwashbur@whittman-hart.com
Tue, 13 Oct 1998 09:26:15 -0500

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Mike:

The short answer to your question is any PRNG you want. Just generate 11
bytes
for versions 2.x+ and 10 bytes for versions less than 2.0. The Zip file
specification
(appnote.txt) is silent on the point.

Specifically, I am pretty sure, (as an ex-employee) PKZIP uses rand() from
the
C library. If not, it is still a Linear Congruential Multiplier PRNG. I
have no
clue what WinZip uses. Hopefully, it is not rand().

>
> Anyone know what prng PKZIP and/or WinZip uses? (The spec asks for 11
> random bytes as a kind of IV for the encryption).
> --
> Mike Stay
> Cryptographer / Programmer
> AccessData Corp.
> mailto:staym@accessdata.com

In Liberty,
John Washhburn

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