Using the Collision Attack for Breaking Cryptographic Modes

Presently the cipher system that is considered to be the industry gold standard is the Advanced Encryption Standard paired with the Cipher Block Chaining cryptographic mode (AES with CBC). The key space and randomization create such a large problem that even a Brute Force attack is thought to be mathematically infeasible. However, separate research by McGrew and Carlson has resulted in an attack known as either the Improbability or Collision attack that shows that the system can be broken with a reasonable amount of input data. In this paper, we present the attack, along with background mathematics, an example, and the experimental results reached by a team led by Carlson. Extensions to other modes are also presented, with the suggestion that the side channel attack renders modes futile. In fact, applying modes reveals so much information that employing them may even compromise the security of the transmitted message.