An 8-bit linear feedback shift register with connection polynomial C(X) = 1+aX +bX^2 +cX^3 +dX^4 +eX^5 + fX^6 +gX^7 +hX^8 is used to generate a pseudo-random binary sequence. This pseudo-random sequence is used as the enciphering key of a stream cipher. It is known that when the cipher is applied to the plaintext string [0,0,0,1,0,0,0,0,1,1,0,0,1,0,1,0,0,1,1,1,0,1,0,1,1,0,1,1,0,1] the corresponding ciphertext string is [0,1,0,0,0,1,1,0,0,0,0,0,0,0,1,0,1,1,1,0,0,1,1,1,0,1,0,0,1,1]. Determine the coefficients of the connection polynomial
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How do I go about determining the key bits? – Pkr96 Mar 12 '18 at 09:03
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I've obtained the key bits to be [0,1,0,1,0,1,1,0,1,1,0,0,1,0,0] – Pkr96 Mar 13 '18 at 13:57
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Determine the key bits first.
Then write down the equations on $a, \ldots h$. Solve.
Henno Brandsma
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