Question

Used on block ciphers. A known plaintext attack. Uses approximation to describe behaviors of block cipher. Given sufficient pairs of plaintext & cipher test, information can be obtained.

A) Differential Cryptanalysis
B) Linear Cryptanalysis
C) Frequency Analysis
D) Brute Force Attack

Answer 1

The subject of this question is Cryptography, specifically focused on the Known Plaintext Attack technique used in cryptanalysis.

Step-by-step explanation:

The subject of this question is Cryptography, which falls under the broader category of Computers and Technology. The specific concept being discussed is Known Plaintext Attack, which is a method used in cryptanalysis to obtain information about a block cipher when both the plaintext and corresponding ciphertext are known.

One of the techniques used in known plaintext attacks is Differential Cryptanalysis. This approach analyzes the differences in encryption outputs for different plaintext pairs to deduce information about the cipher. Another option mentioned, Linear Cryptanalysis, looks for linear relationships between the plaintext, ciphertext, and the key. Frequency Analysis is a unrelated technique that focuses on analyzing the frequency distribution of letters or patterns in a ciphertext to derive information about the underlying plaintext.

A brute force attack, on the other hand, involves trying every possible key in order to decrypt the ciphertext. While it may eventually yield the correct key, it is generally considered less efficient compared to the known plaintext attacks.