Remote locking Project

gooch2k9

I'm looking into making a remote control locking system for my third year electronic engineering project next year in college. I've been informed that it would be a difficult project involving encryption for security.

I was wondering if anyone here could give any advice or information which would be relevant to this project? Cheers.

mazthespark

remote locking of wat? would it be over a long or short range?

Jnealon

A bit more info might help but for my third year project I approached two manufacturers who were extremely helpful. One even called in to the control lab in college with parts for me, all for free.

gooch2k9

Basically I'm looking to design a remote control locking system like you would find in a car. It wouldn't have to work more than 20 feet say. My idea was just to design a demo model of the lock, correct size for a car door but not actually fitted. As many features of such commercial implementations of this product would also be included, ie security.
Hope that helps, any more info needed just ask.

DublinDilbert

As your doing electronic engineering i assume your more interested in the electronics to control the lock rather than the locking mechanism itself.

There are various ways this has been done in the past and is currently done, both from a hardware point of view & data point of view.

You should start reading up on rolling codes and why they are important in security applications. Know the basic theory behind them, why they are important (replay attack), how they are implemented, Problems involved with synchronization etc.

A rolling code algorithm is no good without some sort of encryption. Many implementations use the microchip keyloq algorithm. If your coding from scratch maybe you should implement something like AES encryption. You should be able to simulate your Rolling code, Encrypt & Decrypt algorithms in C on your PC before going near a target system.

You'll then need to come up with a target system, you could just do unidirectional ASK/FSK communications as this widely used. Your receiver module should have some drivers on it to drive the door/boot opening/locking solenoids. If you need to get these solenoids maplin sell them very cheaply.

If you want to do something more up to-date, you should try implement a passive entry system. These would involve both LF + RF bi directional communications, and many of the above issues.

gooch2k9

I've never done encryption in C, is it hard to get into?

Cheers for the advice on what to research for it.

DublinDilbert

gooch2k9 wrote: »

I've never done encryption in C, is it hard to get into?

Cheers for the advice on what to research for it.

How much do you know about encryption?? Well its "only" going to be symmetrical encryption, which is based on substitution and transposition, no modulo arithmetic needed

AES would be over kill for this application. At the end of the day if someone wants to get into the car they can just smash a window

Its a nice project, you can bring it to a number of area's.

Definitely deal with the issue of key distribution! this is important to the security of any encryption system. Would all vehicles have the same encryption / decryption key? If this was read out of one of the ECUs could it compromise the security on all vehicles of that make/model?

gooch2k9

Umm i know that it stops unauthorised chaps from reading data...haven't a clue about implementation or anything. Plenty of research to be done I would say.

Wouldn't mind doing the AES if it was feasible, it would be good experience and would stand to me in the future.

Owen

Maplins do a 2 channel remote kit for 55 euro. Not sure if you need to come up with your own kit or not, but it would be at least handy to scavenge parts from. I wired one of the channels to use my pre-heater in the car.

DublinDilbert

A quick google gives this:-
http://www.hoozi.com/post/829n1/advanced-encryption-standard-aes-implementation-in-c-c-with-comments-part-1-encryption

You'll probably want to implement it on a pic:-
http://edipermadi.wordpress.com/2008/09/25/mini-aes-implementation-on-pic16f84/

Red Alert

You could try implement a public key authentication between the lock and control card?