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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original message
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algorithm for transforming plaintext to ciphertext
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recovering plaintext from ciphertext
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*field of both cryptography and cryptanalysis
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Detailed explanation-1: -This process of recovering the original plaintext from a ciphertext is called decryption. Most encryption algorithms use a key as part of the encryption/decryption process.
Detailed explanation-2: -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-3: -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-4: -Cryptographic attacks are used by cryptanalysts to recover plaintext without a key.