My 2 cents on the subject... The automatic toll fee system I am most familiar with is that of Kapsh (used to be Combitech). They have implemented automatic toll fee collection in many countries around the world (in Europe, Asia, Australia, south America)...
http://www.kapsch.se/ I think they usually implement a combination of 1) a system that queries a device in the car, which identifies the car owner, and then charges the owner in a central database (incrementing the amount that is due) 2) license plate scanning for accountability purposes. When you do crypto to authenticate the communication between the toll device and the device in the car, you need to do fast crypto. Where I work, we used to be in the hardware arena and had a project designing an HSM for a toll fee system. The requirements where that it had to be based on DES/3DES and you had to be able to do DES/3DES operations on single, small length messages, rapidly. This last part is a bit tricky, it's not the same as getting good average speed on longer messages, you need to take into account the communication between the PC and the HSM which accounts for allot of overhead on a single, small length message; IO memory mapping is a good way to go, also preparing keys in RAM can help just a bit, but for us IO memory mapping gave the most significant speed-up. There a paper from IBM on this subject (can't find the reference now), with the same conclusions. License plate scanners seem to be effective these days. I related story to the toll fee license plate scanning, Toronto police are using a license plate recognition device to scan parked cars in order to attempt to identify stolen cars: http://www.ipc.on.ca/scripts/index_.asp?action=31&P_ID=14285&N_ID=1&PT_ID=10 01&U_ID=0 They were able to recover 153 stolen cars in a 3-month test period. They say they can scan 1000 license plates an hour, but this includes the time to send the information to a central point and do a search in a repository. --Anton --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]
