DPA-resistance without routing constraints? - A cautionary note about MDPL security

Abstract

MDPL is a logic style claiming to provide resistance against Differential Side Channel Analysis on power consumption measurements. In this paper we show that the power consumption of a non-linear MDPL gate can be reliably exploited to determine signal values and hence secret data, if the random masks have a slight bias. We present an attack methodology and a case study on how to infer secret key bits of an MDPL secured AES-ASIC in practice by attacking a single MDPL AND gate in a VLSI circuit. Our attack is not based on frequently made assumptions on circuit "anomalies", but on the per definition unbalanced routing, realistic PRNG biases, and knowledge of the circuit layout. © Springer-Verlag Berlin Heidelberg 2007.