Encryption in pics - why?

[Darrel Taylor]

Here's an interesting PDF file from Microchip that describes 4 different encryption techniques for the 18F chips. Unfortunately the actual modules available for download are written for C or assembly, but the PDF gives some good info on how it's done.
Data Encryption Routines for the PIC18   AN953
http://ww1.microchip.com/downloads/e...tes/00953a.pdf

Or, this one for 16F's
Advanced Encryption Standard Using the PIC16XXX   AN821
http://ww1.microchip.com/downloads/e...tes/00821a.pdf

and finally, how does the pic's code protect work?

Other than what's in the data sheets, it's hard to say. But, here's a couple of ways it doesn't work.

This site shows how to retrieve data from a code protected 12C508A.
http://www.rampantapathy.co.uk/12c508a.html

The 16C84 seems to be the easiest to defeat.
http://www.brouhaha.com/~eric/pic/84security.html

Darrel