An NLFSR-Based Stream Cipher
Berndt M. Gammel, Rainer Göttfert, Oliver Kniffler · 2006
We propose a hardware oriented 80-bit-key binary additive stream cipher. The keystream generator consists of ten nonlinear feedback shift registers whose output sequences are combined by a Boolean function of algebraic degree four. The design size of the keystream generator is about 2200 GE. In 130nm CMOS-technology, a throughput of more than 1 Gbps can be achieved. The length of the initial value used for resynchronization can be any multiple of eight between zero and eighty. The maximum amount of keystream that can be used between two resynchronization steps is 2/sup 68/ bits. A parallel implementation of the stream cipher produces one byte of keystream per clock cycle.