Subject: LFSRs

Cryptography computer science

Can someone help me in this question in the figure below ?

(c) (15 points) Show that the period of the combined LFSRs given in Figure 1 is 210. Period of LFSR1 is 2 and outputs 1, 0, 1,0, 1,0... sequence. Periods of LFSR2 and LFSR3 are 7 and 15 respectively Clock LFSR 1 LFSR 3 . Figure 1: Graphical representation of combined LFSRs (O: bitwise AND operation, Bc bitwise EXOR operation, incoming dot-arrow of a LFSR denotes its clock) (c) (15 points) Show that the period of the combined LFSRs given in Figure 1 is 210. Period of LFSR1 is 2 and outputs 1, 0, 1,0, 1,0... sequence. Periods of LFSR2 and LFSR3 are 7 and 15 respectively Clock LFSR 1 LFSR 3 . Figure 1: Graphical representation of combined LFSRs (O: bitwise AND operation, Bc bitwise EXOR operation, incoming dot-arrow of a LFSR denotes its clock)