Cisco Flash help needed

Fri Feb 9 14:24:22 UTC 2001

>I've come across 2 CRCs so far - a 32 bit one used on the Class A cards, 
>and a 16 bit one used on the Class B cards. I've tried a standard crc32 
>routine (stolen from ssh), but it doesn't match the CRC reported by the 
>router. Is there anyone good at understanding CRC routines who can help me 
>reverse-engineer the cisco CRC, or perhaps does someone have some inside 
>information they would like to share?

After some suggestions from various people, I tried uploading a few test 
files onto a Cisco and seeing how the CRCs worked out. It turns out it's 
not a true CRC at all, but rather a variation on the TCP checksum 
algorithm.

>Please don't ask me for the code yet! I'll let the list know when it's 
>available...

v0.1 of the code is now available (read only at the moment):

	ftp://ftp.bbc.co.uk/pub/ciscoflash/

Enjoy,

Simon
-- 
Simon Lockhart                       |   Tel: +44 (0)1737 839676 
Internet Engineering Manager         |   Fax: +44 (0)1737 839516 
BBC Internet Services                | Email: Simon.Lockhart at bbc.co.uk 
Kingswood Warren,Tadworth,Surrey,UK  |   URL: http://support.bbc.co.uk/