GATE | GATE CS 2021 | Set 2 | Question 44

Consider the cyclic redundancy check (CRC) based error detecting scheme having the generator polynomial X³+X+1. Suppose the message m₄m₃m₂m₁m₀ = 11000 is to be transmitted. Check bits c₂c₁c₀ are appended at the end of the message by the transmitter using the above CRC scheme. The transmitted bit string is denoted by m₄m₃m₂m₁m₀c₂c₁c₀. The value of the checkbit sequence c₂c₁c₀ is
(A) 101
(B) 110
(C) 100
(D) 111

Answer: (C)
Explanation: X3+X+1 can be written as 1011, so we will append three 0’s at the end of the message.

The value of the checkbit sequence c2c1c0 is 100.
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