Keeloq
Keeloq (proper spelling " KEELOQ " ) is a conditional access system of the company Microchip Technology Inc.. Its special feature is the dynamically changing code.
Keeloq uses a proprietary, non-linear encryption algorithm with a single key that long of a 32 -bit initialization vector and a 32 -bit rolling code there. During the use, a new code is transmitted. Such systems are often referred to as a rolling code process.
KeeLoq is used in many electronic remote keys to the door opening at cars from companies such as Chrysler, Daewoo, Fiat, General Motors, Honda, Toyota, Lexus, Volvo and Jaguar. In addition Keeloq is used as building access control system and garage door opener.
A variant of the algorithm ( "Friend -or- Foe "), which uses a challenge -response method can also be used for the electronic immobilizer. However, this is not in use at the above-mentioned companies.
On 31 March 2008 a group of scientists led by Christof Paar by the Ruhr- University Bochum announced to have overcome the encryption system using a side-channel attack. This is the power consumption of the microcontroller, to which the encryption algorithm is carried out, is measured with an oscilloscope and analyzed. These side-channel attack has been known since the late 90s in the cryptographic research. One consequence of the Bochum- attack is that a digital key can be copied to the interception of two regular messages. With the intercepted key it is possible to get ( such as a garage ) to gain access to the system. It is also possible to adjust the count of the hopping code on the receiving end so that the rightful owner access is denied.