Paper 2012/509

On 3-share Threshold Implementations for 4-bit S-boxes

Sebastian Kutzner and Phuong Ha Nguyen and Axel Poschmann and Huaxiong Wang

Abstract

One of the most promising lightweight hardware countermeasures against SCA attacks is the so-called Threshold Implementation (TI) countermeasure. In this work we resolve many of the remaining open issues towards it's applicability. In particular, our contribution is three-fold: first we define which optimal (from a cryptographic point of view) S-boxes can be implemented with a 3-share TI. Second, we introduce two methodologies to efficiently implement these S-boxes. Third, as an example, we successfully apply these methodologies to PRESENT and are able to decrease the area requirements of its protected S-box by 57\%.