NETWORK SECURITY
CONFIDENTIALITY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The Initial Permutation table/matrix is of size
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16×8
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12×8
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8×8
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4×8
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Explanation:
Detailed explanation-1: -Explanation: There are 64 bits to permute and this requires a 8×8 matrix.
Detailed explanation-2: -DES is a block cipher that operates on data blocks of 64 bits in size. DES uses a 64-bit key 8 × 8 including 1 bit for parity, so the actual key is 56 bits.
Detailed explanation-3: -Initial permutation Fixed, known mapping 64-64 bits. Key transformations Circular L shift of keys by A(i) bits in round (A(i) is known and fixed). Compression Permutation Fixed known subset of 56-bit input mapped onto 48-bit output.
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