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Answer the following short-answer questions:
• Which of the following is not the principal goal of the cryptography? Select among Confidentiality, Integrity, Availability
• Which of the following is the principal goal of encryption? Select among Confidentiality, Integrity, Availability
• What is a cipher?
• How many keys are used in a secure communication between two parties that use a symmetric-key encryption algorithm?
• What might be the size of an encrypted message, if the size of the plain text 15 bits. You can choose more than one. Select among 14 bit, 15 bits, 16 bits
Question 2
Any encryption operation uses a cipher and a key. Explain the Caesar cipher and the possible keys used by giving an example.
Question 3
Describe the terms permutation, substitution, and the mode of operation. Provide examples to these terms in the context of the Vigenere Cipher.
