The role of Shift Register Cascades in Cryptography? Clearly, there are stages when binary bits are needed and this can be done with the help of Linear Feedback Shift Registers.
Registers are required to be connected in such a manner that one register controls the clock.
can someone explain me more: 


The role of Shift Register Cascades in Cryptography?
Linear Feedback Shift Registers can not safely be used as Cryptographically Secure Pseudo-Random Number Generator (e.g. for the keystream of a stream cipher), because the state  of any LFSR is easily recovered from this output. Even it's structure can, using e.g. the Berlekamp-Massey algorithm.

In cryptography, Shift Register Cascades combine multiple LFSRs (or variants) into hopefully more secure CSPRNGs. Examples include the Alternating Step Generator, and A5/1. Arguably, the modern Trivium is a sort of Shift Register Cascade (which does not use clock control like the previous two, but instead uses a more complex feedback scheme).

Shift Register Cascades tend to inherit the main quality of LFSRs: simple hardware implementation.