COMPUTER FUNDAMENTALS

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COMPUTER ETHICS AND SECURITY

CRYPTOGRAPHY AND ENCRYPTION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Consider the process of encoding and decoding a message using the following Caesar cipher encoding scheme in which the plaintext and ciphertext alphabets are offset by four positions, as shown below:Plaintext: a b c d e f g h i j k l m n o p q r s t u v w x y z Ciphertext: w x y z a b c d e f g h i j k l m n o p q r s t u v Which of the following encoded ciphertext strings decodes to an original plaintext message of “secret”?
A
etsecr
B
wigvix
C
kwujwl
D
oaynap
Explanation: 

Detailed explanation-1: -To decrypt a message encoded with a Caesar cipher, simply take the value of 26 minus the shift value, and apply that new value to shift the encoded message back to its original form.

Detailed explanation-2: -Cryptography is the process of converting between readable text, called plaintext, and an unreadable form, called ciphertext . This occurs as follows: The sender converts the plaintext message to ciphertext. This part of the process is called encryption (sometimes encipherment ).

Detailed explanation-3: -Since there are only a limited number of possible shifts (25 in English), an attacker can mount a brute force attack by deciphering the message, or part of it, using each possible shift.

Detailed explanation-4: -In the generalized version of Caesar’s cipher each alphabet is replaced with another alphabet after shifting it x times to the right. The amount of the shift (x) is the encryption key. More items

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