Kee Loq
KeeLoq is a proprietary hardware-dedicated NLFSR-based block cipher. The uni-directional command transfer protocol was designed by Frederick Bruwer, PhD, CEO at Nanoteq (Pty) Ltd and the cryptographic algorithm was created by Professor Gideon Kuhn with the silicon implementation by Willem Smit, PhD, at Nanoteq Pty Ltd (South Africa) in the mid 80's and sold to Microchip Technology Inc in 1995 for $10 million. It's used in "code hopping" encoders and decoders such as NTQ105/106/115/125D/129D and HCS101/2XX/3XX/4XX/5XX. KeeLoq is or was used in many remote keyless entry systems by such companies as Chrysler, Daewoo, Fiat, GM, Honda, Toyota, Volvo, Volkswagen Group, Clifford, Shurlok, Jaguar, etc.
Read more about Kee Loq: Description, Cryptanalysis, Side-channel Attacks