What are the types of Cryptanalysis Attacks on AES in information security?

There are various types of Cryptanalysis attack on AES which are as follows −

• Linear Cryptanalysis Attack − Linear cryptanalysis is based on discovering affine approximations to the element of a cipher. It tries to take benefit of high probability linear relationship that exist among inputs and outputs of a function block.

In the approach of a block cipher, linear set of plain text pattern and linear set of ciphertext patterns are distinguished to linear set of key bits. The main objective of linear cryptanalysis is to find a relationship that is prove either significantly more or less than 50% of the time.

• Differential Cryptanalysis Attack − Differential cryptanalysis exploits relationships that occur between differences in the input and output of a function block. In the method of an encryption algorithm, plaintext patterns with fixed differences are determined.

The main objective of differential cryptanalysis is to find “characteristics”. Characteristics are specific differences in group of plaintext patterns that, for a given key, have a high probability of generating specific differences in the ciphertext pairs.

A differential attack would include using pairs of plaintext pairs and assigning probabilities to several candidate subkeys. The probabilities will be depends on the cryptanalyst’s knowledge of the algorithm’s characteristics. Enough trails are run such that the proper key can be decided.

In differential cryptanalysis, the importance of the attacker is to analyze the changes in some selected plaintexts and the difference in the outputs resulting from encrypting each one, it is applicable to find some of the key.

• The Boomerang Attack − The boomerang attack introduced by Wagner can be view as an update of classical differential cryptanalysis working on quadruples of data rather than pairs with fixed difference.

Quadruples of plaintexts are perfectly selected, and acquired with correlating quadruples of ciphertexts and middle states. Wagner displayed how to use this attack to some of the lesser known block cipher.

• Truncated Differentials, the Square Attack and Interpolation Attacks − Truncated differentials are a generalization of differential cryptanalysis where partially decided differentials are treated.

These partial differentials provide cluster into pools of difference pairs. This property can return statistics that significantly decrease the difficulty for a successful attack.

The Square attack is a generalization of an attack initially proposed against the Square Block Cipher. For this attack, a “multiset” of plaintexts is carefully selected to have specific properties.

This multiset is used to the algorithm and the propagation of these multisets is then determined through the several rounds. The persistence of these properties provides understanding to the numerical behaviour of the algorithm which can be used to inform bits of key.

For interpolation attacks, the cipher is modeled using a large order polynomial. Thus the polynomial is solved for the key-dependent coefficients. The approach is very efficient when a compact expression of low degree defining the cipher is applicable.

Updated on: 14-Mar-2022

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