UNIT 1 QUIZZ

Use Caesar’s Cipher to decipher the following

HQFUBSWHG WHAW

• ABANDONED LOCK

• ENCRYPTED TEXT

• ABANDONED TEXT

• ENCRYPTED LOCK

Monoalphabetic ciphers are stronger than Polyalphabetic ciphers because frequency analysis is tougher on the former.

• True

• False

On Encrypting “thepepsiisintherefrigerator” using Vignere Cipher System using the keyword “HUMOR” we get cipher text

• abqdnwewuwjphfvrrtrfznsdokvl

• abqdvmwuwjphfvvyyrfznydokvl

• tbqyrvmwuwjphfvvyyrfznydokvl

• baiuvmwuwjphfoeiyrfznydokvl

In brute force attack, on average half of all possible keys must be tried to achieve success.

• True

• False

If the sender and receiver use different keys, the system is referred to as conventional cipher system.

• True

• False

An encryption scheme is unconditionally secure if the ciphertext generated does not contain enough information to determine uniquely the corresponding plaintext, no matter how much cipher text is available.

• True

• False

_______________________ is a term used in cryptography that refers to a message before encryption or after decryption.

• Cipher Text

• Plain Text

• Cipher Script

• Plain Script

A ________ cipher replaces one character with another character.

• substitution

• transposition

• either (a) or (b)

• neither (a) nor (b)

________ is the science and art of transforming messages to make them secure and immune to attacks.

• Cryptography

• Cryptoanalysis

• either (a) or (b)

• neither (a) nor (b)

In a(n) ________ cipher, the same key is used by both the sender and receiver.

• symmetric-key

• asymmetric-key