An algebraic attack on stream ciphers with application to nonlinear filter generators and WG-PRNG
This work addresses security vulnerabilities in stream ciphers, particularly for lightweight cryptography applications, but appears incremental as it builds on existing attacks.
The authors tackled the problem of assessing stream cipher security by proposing a new algebraic attack, showing that WG-PRNG, a cipher submitted to the NIST Lightweight Cryptography competition, has lower security than previously stated.
In this paper, we propose a new algebraic attack on stream ciphers. Starting from the well-known attack due to Courtois and Meier, we design an attack especially effective against nonlinear filter generators. We test it on two toy stream ciphers and we show that the level of security of one of stream ciphers submitted to the NIST competition on Lightweight Cryptography, WG-PRNG, is less than that stated before now.