POK Flag Weirdness wth binary files

From: Wayne Myers (waz_at_easynet.co.uk)
Date: 05/26/04 

Date: 26 May 2004 13:18:38 -0700

Hi,

This week I got bitten by something very strange. I was writing
code that needed to decrypt something encrypted using Rijndael
encryption, but when I read the key in, for some reason, the
Crypt::Rijndael module refused to accept the key as a valid
scalar string.

Digging around in the Crypt::Rijndael code and testing the string
with Devel::Peek revealed that no matter what method I used to
read the key (a stream of random binary digits), the internal POK
flag was not being set. Crypt::Rijndael explicitly tests the POK
flag before accepting a key: this is why that was failing.

However, I am not the first person to come across this problem,
and found an extremely strange workaround here:

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&th=b088f2ae7045eb62&seekm=3CE0C77A.5030404%40hexaflux.com&frame=off

I have written a short script reproducing the problem (under Perl
5.6.1 and Perl 5.8.3) and demonstrating the same workaround, here:

http://www.waz.easynet.co.uk/pok/pok.pl.txt

Is it a bug in Perl, a bug in Crypt::Rijndael, or a bug in my
understanding of how to read in binary files?

I'd be grateful if anyone could help me shed light on the matter

Cheers etc.,

Wayne 

-- 
Wayne Myers
http://www.waz.easynet.co.uk/

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