What type of cryptanalysis examines differences in input and how that affects the resultant differences in output?

Differential cryptanalysis is a method that focuses on how changes in the input of a cryptographic algorithm can affect the output. It studies the relationship between the plaintext differences and the resulting ciphertext differences after encryption. This type of analysis is particularly effective against block ciphers and can help in revealing weaknesses based on these input-output relationships.

In differential cryptanalysis, attackers take pairs of plaintexts that have specific differences and analyze how these differences propagate through the encryption process. The goal is to find patterns in the resulting ciphertext differences that can be exploited to break the cipher or discover the secret key.

This approach distinguishes itself clearly from other forms of cryptanalysis. Frequency analysis, for instance, relies on the frequency of occurrence of letters or groups of letters in a ciphertext rather than the differences in input values. Linear cryptanalysis detects linear approximations between plaintext, ciphertext, and key bits but does not focus on input/output differences in the same manner. A known-plaintext attack involves having both the plaintext and corresponding ciphertext to derive the key, but it does not specifically analyze the differences between inputs and outputs like differential cryptanalysis does.