KeeLoq is a proprietary hardware-dedicated block cipher that uses a non-linear feedback shift register (NLFSR). The uni-directional command transfer protocol was designed by Frederick Bruwer of Nanoteq (Pty) Ltd., the cryptographic algorithm was created by Gideon Kuhn at the University of Pretoria, and the silicon implementation was by Willem Smit at Nanoteq Pty Ltd (South Africa) in the mid-1980s. KeeLoq was sold to Microchip Technology Inc in 1995 for $10 million. It is used in "code hopping" encoders and decoders such as NTQ105/106/115/125D/129D, HCS101/2XX/3XX/4XX/5XX and MCS31X2. 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, and Jaguar.