COMPUTER NETWORKS AND COMMUNICATIONS
NETWORK SECURITY AND CYBERSECURITY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Encrypt “cryptosystem” with key 7 using Shift Cipher
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jygwhvjfkalt
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jyfuarzfzopt
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jyfwavzfzalt
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jyfwaerfzret
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Explanation:
Detailed explanation-1: -Here (9, 15) is the decryption key for the affine cipher with encryption key (3, 7). y + 19 ≡ 3x (mod 26). 9(y + 19) ≡ 9 · 3x ≡ x (mod 26).
Detailed explanation-2: -Use the shift cipher with key = 15 to decrypt the message “WTAAD.” A transposition cipher reorders ( t ) b l i bl k f (permutes) symbols in a block of symbols.
Detailed explanation-3: -How to decrypt using the shift cipher? Decryption requires knowing the shift used and the alphabet. Take a letter in position N in the alphabet that has been encrypted by a shift of X, it must be shifted by-X to return to its original position N-X .
There is 1 question to complete.