The Role of Major and Minor Collisions in Side Channel Attacks

摘要

The security of cryptographic algorithms such as block ciphers and public-key algorithms relies on the secrecy of the key. Traditionally, when cryptanalysists examine the security of a cryptographic algorithm, they try to recover the secret key by observing the inputs and outputs of the algorithm. Assuming this type of attack models, cryptologists have made commonly-used cryptographic algorithms secure against such attacks. However, a real computing device not only generates the outputs specified in algorithms but also inevitably produces some other information such as timing and power. These types of information, called side-channel information, can be exploited in side-channel attacks to retrieve secret keys. Side channel attacks have successfully broken many algorithms. The attacker obtains the value of secret key at single instance some iteration is called Major Collisions. The attacker gains two values of random integer at some iteration are called Minor Collisions.We have provided a brief background on Simple (SPA) and Differential (DPA) power and electromagnetic analysis attacks on the classical ECSM algorithms. We study on minor collisions and to provide an analytic result for their probability of occurrence as well as effect of the fixed sequence window method. We prove that mathematically the minor collisions are reduced up to 50% of major collisions. We analysis the role of Major and Minor collisions in side channel attacks.