Improved Secure Implementation of Code-Based Signature Schemes on Embedded Devices.
Arnaud Dambra, Philippe Gaborit, Mylène Roussellet, Julien Schrek, Nicolas Tafforeau · 2014
Abstract. Amongst areas of cryptographic research, there has recently been a widening interest for code-based cryptosystems and their implementations. Besides the a priori resis-tance to quantum computer attacks, they represent a real alternative to the currently used cryptographic schemes. In this paper we consider the implementation of the Stern authenti-cation scheme and one recent variation of this scheme by Aguilar et al.. These two schemes allow public authentication and public signature with public and private keys of only a few hundreds bits. The contributions of this paper are twofold: first, we describe how to imple-ment a code-based signature in a constrained device through the Fiat-Shamir paradigm, in particular we show how to deal with long signatures. Second, we implement and explain new improvements for code-based zero-knowledge signature schemes. We describe implementa-tions for these signature and authentication schemes, secured against side channel attacks, which drastically improve the previous implementation presented at Cardis 2008 by Cayrel et al.. We obtain a factor 3 reduction of speed and a factor of about 2 for the length of the signature. We also provide an extensive comparison with RSA signatures.