Analysis of Non-fortuitous Predictive States of the RC4 Keystream Generator

The RC4 stream cipher is the most widely used software based stream cipher. It is based on a secret internal state of N = 256 bytes and two pointers. This paper proposes an efficient algorithm to compute a special set of RC4 states named non-fortuitous predictive states. These special states increase the probability to guess part of the internal state in a known plaintext attack and present a cryptanalytic weakness of RC4. The problem of designing a practical algorithm to compute them has been open since it was posed by Mantin and Shamir in

• Type: Conference
• Year: 2003
• Where: INDOCRYPT
• Authors: Souradyuti Paul, Bart Preneel
• Keywords: INDOCRYPT 2003, Internal State, RC4 Stream Cipher, Secret Internal State