Research Article
Cryptanalysis of Salsa and ChaCha: Revisited
@INPROCEEDINGS{10.1007/978-3-319-90775-8_26, author={Kakumani Deepthi and Kunwar Singh}, title={Cryptanalysis of Salsa and ChaCha: Revisited}, proceedings={Mobile Networks and Management. 9th International Conference, MONAMI 2017, Melbourne, Australia, December 13-15, 2017, Proceedings}, proceedings_a={MONAMI}, year={2018}, month={5}, keywords={Stream cipher eSTREAM Salsa ChaCha Non-randomness Quarterround Reverseround Valid states Probabilistic neutral bit (PNB) ARX cipher}, doi={10.1007/978-3-319-90775-8_26} }- Kakumani Deepthi
Kunwar Singh
Year: 2018
Cryptanalysis of Salsa and ChaCha: Revisited
MONAMI
Springer
DOI: 10.1007/978-3-319-90775-8_26
Abstract
Stream cipher is one of the basic cryptographic primitives that provide the confidentiality of communication through insecure channel. EU ECRYPT network has organized a project for identifying new stream suitable for widespread adoption where the ciphers can provide a more security levels. Finally the result of the project has identified new stream ciphers referred as eSTREAM. Salsa20 is one of the eSTREAM cipher built on a pseudorandom function. In this paper our contribution is two phases. First phase have two parts. In WCC 2015, Maitra et al. [9] explained characterization of valid states by reversing one round of Salsa20. In first part, we have revisited the Maitra et al. [9] characterization of valid states by reversing one round of Salsa20. We found there is a mistake in one bit change in and word in first round will result in valid initial state. In second part, Maitra et al. [9] as mentioned that it would be an interesting combinatorial problem to characterize all such states. We have characterized nine more values which lead to valid initial states. The combinations , , , , , , , and which characterized as valid states.
