Cryptography Reference
In-Depth Information
Chapter 14
Fault Attacks on Stream Ciphers
Alessandro Barenghi and Elena Trichina
Abstract
In this chapter, we provide an outlook on fault attack techniques aimed
at breaking stream ciphers. The chapter will start with an overview of the possible
targets for fault attacks among this class of encryption algorithms, and subsequently
provide two in-depth case studies on enhancing impossible cryptanalysis against
RC4 and differential cryptanalysis against Trivium. After the analysis the chapter
will end with a broader overview of the attacks on other notable stream ciphers and
provide directions for future research in the field.
14.1 Introduction
Prior to the appearance of fast block ciphers, such as DES, stream ciphers ruled
the world of encryption. The classical examples of such ciphers are rotor machines,
among which Enigma occupies the most prominent place. Although the methods of
design and analysis of block and stream ciphers are quite different, the distinction
between them nowadays is somewhat vague. One of the main reasons why modern
state-of-the-art stream ciphers seem to be not as well defined as block ciphers is
because of the great variety of their constructions and because, with the advent
of sophisticated computers, communications do not happen bit-by-bit anymore but
in multi-bit packets. This trend has pushed the use of fast software-oriented block
ciphers in a stream-like direction, thanks to special modes of operations, such as
Counter, Output FeedBack, Cipher Block Chaining and Galois Counter modes. A
confirmation of this trend is the adoption of the KASUMI stream cipher as a 3GPP
