Suppose that a key stream is generated for a stream cipher by using the following linear recurrence over Z2 of degree 3: Zi+3 = (zi + zi+2) mod 2 for i > 1. For the initial vector (21, 22, 23) = (1,0,1), find the first 10 elements of the key stream. 1010011101 1010010011 1011011010 1011011011 1011101110 Find the period of the resulting key stream. 7 3 9 8 10 By using Autokey Cipher with the key k = 5, decrypt: NOUHBBWRBR Enter your plaintext below with exactly one word in each box in the order