COMPUTER ETHICS AND SECURITY
CRYPTOGRAPHY AND ENCRYPTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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ATTACK AT DAWN
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HELLO WORLD
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I LOVE GAMES
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CODING ROCKS
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Detailed explanation-1: -To decrypt, take the first letter of the ciphertext and the first letter of the key, and subtract their value (letters have a value equal to their position in the alphabet starting from 0). If the result is negative, add 26 (26=the number of letters in the alphabet), the result gives the rank of the plain letter.
Detailed explanation-2: -To decrypt a message, you reverse the process by first finding the row that corresponds to the current letter in the key, then looking along that row until you find the corresponding letter in the ciphertext. The letter at the top of this column is the plaintext letter.
Detailed explanation-3: -Cryptographic ciphers are used to convert ciphertext to plaintext and back. With symmetric key algorithms, the same key is used for the encryption and decryption of data. Asymmetric key algorithms use public keys and private keys to encrypt and decrypt data.
Detailed explanation-4: -Block ciphers transform plaintext 1 block (64/128/256 bits) at a time, while stream ciphers convert plaintext to ciphertext 1 byte at a time.