PNB Based Differential Cryptanalysis of Salsa20 and ChaCha

This paper introduces significant improvements over the existing cryptanalysis approaches on Salsa20 and ChaCha stream ciphers. For first time, we reduced attack complexity Salsa20/8 to lowest possible margin. We introduced an ChaCha7.25. It is of its type ChaCha7.25/20. In our approach, studied differential ciphers based a comprehensive analysis probabilistic neutral bits (PNBs). The study bias at specific input output positions then search for bits. However, set PNBs obtained in this method are not always ideal combination conduct against researchers have focused neutrality measure all key concerning difference internal rounds Moreover, relationship between number inverse quarter has been scrutinized yet. To address these gaps, reduced-round ChaCha. At first, comprehensively analyze 256 positions. Afterward, select bit position with best average look corresponding bias. Considering aspects, present time 2241.62 data 231.5, which best-known single then, ChaCha7.25 2254.011 251.81.