International Association
for Cryptologic Research

Side channel analysis and active fault analysis are

now major threats to even mathematically robust cryptographic

algorithms that are otherwise resistant to classical cryptanalysis.

It is necessary to design suitable countermeasures to protect

cryptographic primitives against such attacks. This paper focuses

on designing encryption schemes that are innately secure against

fault analysis. The paper formally proves that one such design

strategy, namely the use of key-dependent SBoxes, is only

partially secure against DFA. The paper then examines the

fault tolerance of encryption schemes that use a key-independent

secret tweak value for randomization. In particular, the paper

focuses on a linear tweak based and a non-linear tweak based

version of a recently proposed block cipher DRECON. The paper

demonstrates that while both versions are secure against classical

DFA, the non-linear tweak based version provides greater fault

coverage against stronger fault models. This fact, together with

the DPA resistance provided by the use of variable S-Boxes,

makes DRECON a strong candidate for the design of secure

cryptographic primitives. All claims have been validated by

experimental results on a SASEBO GII platform.