TRUE OR FALSE
T F 1. Symmetric encryption remains by far the most widely used of the
two types of encryption.
T F 2. Rotor machines are sophisticated precomputer hardware devices
that use substitution techniques.
T F 3. Symmetric encryption is a form of cryptosystem in which
encryption and decryption are performed using different keys. It is
also known as non- conventional encryption.
T F 4. With the use of symmetric encryption, the principal security
problem is maintaining the secrecy of the key.
T F 5. The process of converting from plaintext to ciphertext is known as
deciphering or decryption.
T F 6. The algorithm will produce a different output depending on the
specific secret key being used at the time. The exact substitutions
and transformations performed by the algorithm depend on the
key.
T F 7. When using symmetric encryption it is very important to keep the
algorithm secret.
T F 8. On average, half of all possible keys must be tried to achieve
success with a brute-force attack.
T F 9. Ciphertext generated using a computationally secure encryption
scheme is impossible for an opponent to decrypt simply because
the required information is not there.
T F 10. Monoalphabetic ciphers are easy to break because they reflect the
frequency data of the original alphabet.
T F 11. As with Playfair, the strength of the Hill cipher is that it
completely hides single letter frequencies.
T F 12. A scheme known as a one-time pad is unbreakable because it
produces random output that bears no statistical relationship to
the plaintext.
T F 13. The one-time pad has unlimited utility and is useful primarily for
high-bandwidth channels requiring low security.
T F 14. The most widely used cipher is the Data Encryption Standard.
T F 15. Steganography renders the message unintelligible to outsiders by
various transformations of the text.