{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:36:53Z","timestamp":1787031413384,"version":"build-2736575974"},"reference-count":0,"publisher":"Universitatsbibliothek der Ruhr-Universitat Bochum","issue":"2","license":[{"start":{"date-parts":[[2024,6,18]],"date-time":"2024-06-18T00:00:00Z","timestamp":1718668800000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["ToSC"],"abstract":"<jats:p>ChaCha is a well-known stream cipher that has been used in many network protocols and software. In this paper, we study the security of reduced round ChaCha. First, by considering the differential-linear hull effect, we improve the correlation of a four-round differential-linear distinguisher proposed at FSE 2023 by providing other intermediate linear masks. Then, based on the four-round differential-linear distinguisher and the PNB method, by using the assignment 100 \u00b7\u00b7\u00b7 00 for consecutive PNBs, higher backward correlation is obtained and improved key recovery attacks of 7-round and 7.25-round ChaCha are obtained with time complexity 2189.7 and 2223.9, which improve the previously best-known attacks by 217.1 and 214.44, respectively. Finally, we consider the equivalence of the security between (R + 0.25)-round and (R + 0.5)\u2295-round ChaCha, and show that (R + 0.25)-round and (R + 0.5)\u2295-round ChaCha provide the same security against chosen(known) plaintext attacks. As a result, improved differential-linear cryptanalysis of 7.5\u2295-round ChaCha can also be obtained similarly to that of 7.25-round ChaCha, which improves the previously best-known attack by 219.<\/jats:p>","DOI":"10.46586\/tosc.v2024.i2.166-189","type":"journal-article","created":{"date-parts":[[2024,6,19]],"date-time":"2024-06-19T10:36:24Z","timestamp":1718793384000},"page":"166-189","source":"Crossref","is-referenced-by-count":11,"title":["Differential-Linear Cryptanalysis of Reduced Round ChaCha"],"prefix":"10.46586","volume":"2024","author":[{"given":"Zhichao","family":"Xu","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hong","family":"Xu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lin","family":"Tan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wenfeng","family":"Qi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"25480","published-online":{"date-parts":[[2024,6,18]]},"container-title":["IACR Transactions on Symmetric Cryptology"],"original-title":[],"link":[{"URL":"https:\/\/tosc.iacr.org\/index.php\/ToSC\/article\/download\/11626\/11116","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/tosc.iacr.org\/index.php\/ToSC\/article\/download\/11626\/11116","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,19]],"date-time":"2024-06-19T10:36:25Z","timestamp":1718793385000},"score":1,"resource":{"primary":{"URL":"https:\/\/tosc.iacr.org\/index.php\/ToSC\/article\/view\/11626"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,6,18]]},"references-count":0,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2024,6,18]]}},"URL":"https:\/\/doi.org\/10.46586\/tosc.v2024.i2.166-189","relation":{},"ISSN":["2519-173X"],"issn-type":[{"value":"2519-173X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,6,18]]}}}