Chapter 21.2, Problem 4SC

Explanation of Solution

Decryption of the given message:

• The given message is “Khoor/#Zruog$”.
• The user carrying out any encryption chooses an encryption key, where an encryption key is a number between “1”, and “255”.
• The user can use Caesar cipher to encrypt a message with a key of “3”.
• The shift which is to be used in each byte which is to be encrypted is indicated by that number.
• The user carrying out any decryption chooses the decryption key, which is the negative of the encryption key.
• The user can use Caesar cipher to decrypt a message encrypted with a key of “3”, with a key of “-3”.
• The shift which is to be used in each byte which is to be decrypted is indicated by the decryption key.
• The letter “K” in the given message is replaced with “H”.
• The letter “h” is replaced with “e”...