Profiled Time-Driven Cache Attacks on Block Ciphers

In 2005, D. J. Bernstein developed a timing attack capable of retrieving the Advanced Encryption Standard (AES) secret key [4]. Unlike the previous attacks discussed so far, Bernstein’s attack has two phases: a profiling phase followed by an attack phase. During the profiling phase, the attacker learns the characteristics of the system by building a timing profile called template using a key which is known to him/her. The template captures all the timing characteristics when AES is executed. With this template, any other secret key used in the AES implementation on that system can be attacked. During the attack phase, another timing profile is built for the secret key. A statistical comparison of this timing profile with the template reveals the secret key. This chapter provides details of the attack and analyzes the information leaked.