Question

A variation on frequency analysis that is used to attack polyaplhabetic substitution ciphers.

A) Vigenère cipher
B) Caesar cipher
C) Kasiski Test
D) Enigma machine

Answer 1

The Kasiski Test is a variation on frequency analysis used to attack polyalphabetic substitution ciphers.

Step-by-step explanation:

The variation on frequency analysis that is used to attack polyalphabetic substitution ciphers is the Kasiski Test. This test involves analyzing repeated patterns in the ciphertext and using them to find the length of the keyword used in the encryption.

Once the length of the keyword is determined, the Kasiski Test helps break the cipher by identifying the possible positions of each letter in the keyword. By discovering these positions, the encryption can be reversed and the original message can be revealed.

This technique is effective against polyalphabetic substitution ciphers, such as the Vigenère cipher, which use multiple alphabets to encrypt the plaintext.