On Thu, 9 Jan 2003, Ralf-Philipp Weinmann wrote: > do you have an actual specification of the algorithm used by the rolling > code system or is that just another ingenious "high-level" whitepaper > leaving out all the nice details ?
No nice details, just whitepaper blurbs. That's why I'm asking! > I tried to find details for rolling code systems used in car keys a > couple of years ago and came up with basically zilch on the specific > algorithms employed by the manufacturers for their challenge reponse > systems. I went to my local hardware store and they have an Ilco tester. It said my key is made by TI. A web search on TI rfid has given me a few clues, but the best I get for the algorithm is a document number which you need an NDA to get. I still don't know if it's the same thing used by Ford, they may have a modified version just to make sure we can't figure it out :-) > Have you tried opening the key and had a look at the chip - doubt this > will help much but to identify since I suspect car manufacturers > customize these with their home-brewn algorithm. This is just an > unfounded speculation on my part however. I just ordered 5 key blanks. 2 for spares and 3 to cut up :-) > Also, I'd be interested where you can get these "replacement keys" for > USD 8, and whether it's for Ford only. I've found a lot of places that sell key blanks for every brand of car. The version I own has no third party supplier, only Strattec makes it. Check out this web site: http://www.nvo.com/deter/transponders/ Turns out I had to pay USD 13, but the older style keys are cheaper. Also do a web search on "immobilizer" and "chip key". Nobody has any cryto details tho, so this is looking loke a fun challenge :-) Patience, persistence, truth, Dr. mike
