Paper 2009/584

Scan-based Attacks on Linear Feedback Shift Register Based Stream Ciphers

Yu Liu, Kaijie Wu, and Ramesh Karri

Abstract

In this paper, we present an attack on stream cipher implementations by determining the scan chain structure of the linear feedback shift registers in their implementations. Although scan Design-for-Test (DFT) is a powerful testing scheme, we show that it can be used to retrieve the information stored in a crypto chip thus compromising its theoretically proven security.