Optimal Recovery of Secret Keys from Weak Side Channel Traces

摘要

It should be difficult to extract secret keys using weak side channel leakage from embedded crypto-systems which employ standard counter-measures. Here we consider the case of key re-use with randomised exponent recoding. An optimum strategy is presented and proved, but it has the disadvantage of impracticality for realistic key sizes. Developed from the basis of an optimal decision strategy, some modified, computationally feasible versions are studied for effectiveness. This shows how to modify existing algorithms and pick their parameters for the best results.