Robust First Two Rounds Access Driven Cache Timing Attack on AES

The memory Cache data access time uncertainty and resource multi-process sharing mechanism provide a new covert channel to leak process secret information. The AES software implementation used many table lookup operations to access cache, and these lookup indices have close relationship with the secret key. According to 128-bit AES, we propose a new robust first two rounds access driven cache timing attack. We use a spy process to gather cache access patterns of AES process, thus get the table lookup indices during one AES encryption, combine certain analysis methods, finally recover 128-bit full AES key. With counter to current belief, our experiments show that, only through the first round attack, 350 samples are enough to recover full AES key. After we extend the attack to the second round, 80 samples are enough to recover full AES key.