Modified version of "Latin Dances Revisited: New Analytic Results of Salsa20 and ChaCha".
Tsukasa Ishiguro · IACR Cryptology ePrint Archive · 2012
In this paper, we improve an analysis algorithm and apply it to cryptanalysis of Salsa and ChaCha. We constructed a distinguisher of double-bit differentials to improve Aumasson’s single-bit differential cryptanalysis. This method has potential to apply to a wide range of stream ciphers; a double-bit correlation would be found in case that no single-bit correlation is found. However, there are no double bit biases of 5 or more round Salsa20 and ChaCha.