CHECKSUM CHALLENGE - (US$ 100)

From: Carlos Gomez (carlos_gomez_73_at_hotmail.com)
Date: 02/11/04


Date: 11 Feb 2004 08:45:36 -0800

CHECKSUM CHALLENGE

We're offering US$100 to have a checksum/CRC algorithm
reverse-engineered.

We have a microcontroller-based system that connects via modem to a
remote PC. The PC runs a software that talks to the microcontroller,
sending and receiving data. The person that developed this system for
us is no longer available.
We have the protocol to control the system but we don't know the
checksum algorithm and therefore can't get the new data accepted by
the receiving machine.
Apparently the last two bytes of each data packet are Checksum/CRC.
The first byte is the number of bytes that follows in the packet (we
don't know if this byte is computed in the Checksum/CRC).

Examples of the data and resultant checksum are provided below.

If interested, please email me for further details. I will let you
know how many others have applied. The money goes to the first one who
returns a working algorithm preferably implemented in VB.

Thanks,

Carlos Gomez
carlos_gomez_73@hotmail.com

06 FF 01 FF 09 FF 46 FF 36 FF D8 FF F5
06 FF 01 FF 09 FF 0A FF 3C FF F1 FF 95
06 FF 01 FF 09 FF 7C FF 2A FF E0 FF A3
06 FF 01 FF 09 FF A6 FF 36 FF D8 FF C1
06 FF 01 FF 09 FF D6 FF 2A FF DE FF 5B
06 FF 01 FF 07 FF 06 FF 1E FF 7D FF D7
06 FF 01 FF 07 FF 24 FF F5 FF 23 FF 91
06 FF 01 FF 08 FF 80 FF 1E FF 22 FF 9D
06 FF 01 FF 08 FF 9E FF 42 FF 72 FF C1



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