Paper 2012/400

An Algebraic Fault Attack on the LED Block Cipher

Philipp Jovanovic and Martin Kreuzer and Ilia Polian

Abstract

In this paper we propose an attack on block ciphers where we combine techniques derived from algebraic and fault based cryptanalysis. The recently introduced block cipher LED serves us as a target for our attack. We show how to construct an algebraic representation of the encryption map and how to cast the side channel information gained from a fault injection into polynomial form. The resulting polynomial system is converted into a logical formula in conjunctive normal form and handed over to a SAT solver for reconstruction of the secret key. Following this approach we were able to mount a new, successful attack on the version of LED that uses a 64-bit secret key, requiring only a single fault injection.

Note: The contents of this paper were presented at the "Third international conference on Symbolic Computation and Cryptography (SCC 2012)" (http://scc2012.unican.es) and in the "Symbolic Computations and Post-Quantum Cryptography" Online Seminar (http://www.stevens.edu/algebraic/SCPQ/)