Linear Ciphers and Random Sequence Generators with Multiple Clocks.

James L. Massey Rainer A. Rueppel Linear Ciphers and Random Sequence Generators with Multiple Clocks. 74-87 http://link.springer.de/link/service/series/0558/bibs/0209/02090074.htm 1984 EUROCRYPT db/conf/eurocrypt/eurocrypt84.html#MasseyR84