 In their paper, "On the Power of Simple Branch Prediction Analysis", the authors of SBPA (Onur Aciicmez and Cetin Kaya Koc) claim to have discovered 508 out of 512 bits of an RSA key in 10 iterations.A power fault attack on RSA implementations has been described in 2010.The author recovered the key by varying the CPU power voltage outside limits; this caused multiple power faults on the server.