{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T17:47:59Z","timestamp":1767980879760,"version":"3.49.0"},"reference-count":0,"publisher":"Universitatsbibliothek der Ruhr-Universitat Bochum","license":[{"start":{"date-parts":[[2021,12,3]],"date-time":"2021-12-03T00:00:00Z","timestamp":1638489600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["ToSC"],"abstract":"<jats:p>In CRYPTO\u201916, Cogliati and Seurin proposed a block cipher based nonce based MAC, called Encrypted Wegman-Carter with Davies-Meyer (EWCDM), that gives 2n\/3 bit MAC security in the nonce respecting setting and n\/2 bit security in the nonce misuse setting, where n is the block size of the underlying block cipher. However, this construction requires two independent block cipher keys. In CRYPTO\u201918, Datta et al. came up with a single-keyed block cipher based nonce based MAC, called Decrypted Wegman-Carter with Davies-Meyer (DWCDM), that also provides 2n\/3 bit MAC security in the nonce respecting setting and n\/2 bit security in the nonce misuse setting. However, the drawback of DWCDM is that it takes only 2n\/3 bit nonce. In fact, authors have shown that DWCDM cannot achieve beyond the birthday bound security with n bit nonces. In this paper, we prove that DWCDM with 3n\/4 bit nonces provides MAC security up to O(23n\/4) MAC queries against all nonce respecting adversaries. We also improve the MAC bound of EWCDM from 2n\/3 bit to 3n\/4 bit. The backbone of these two results is a refined treatment of extended mirror theory that systematically estimates the number of solutions to a system of bivariate affine equations and non-equations, which we apply on the security proofs of the constructions to achieve 3n\/4 bit security.<\/jats:p>","DOI":"10.46586\/tosc.v2021.i4.138-176","type":"journal-article","created":{"date-parts":[[2021,12,3]],"date-time":"2021-12-03T12:10:34Z","timestamp":1638533434000},"page":"138-176","source":"Crossref","is-referenced-by-count":6,"title":["Improved Security Bound of (E\/D)WCDM"],"prefix":"10.46586","author":[{"given":"Nilanjan","family":"Datta","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Avijit","family":"Dutta","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kushankur","family":"Dutta","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"25480","published-online":{"date-parts":[[2021,12,3]]},"container-title":["IACR Transactions on Symmetric Cryptology"],"original-title":[],"link":[{"URL":"https:\/\/tches.iacr.org\/index.php\/ToSC\/article\/download\/9332\/8891","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/tches.iacr.org\/index.php\/ToSC\/article\/download\/9332\/11453","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/tches.iacr.org\/index.php\/ToSC\/article\/download\/9332\/8891","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,12,10]],"date-time":"2024-12-10T14:11:43Z","timestamp":1733839903000},"score":1,"resource":{"primary":{"URL":"https:\/\/tches.iacr.org\/index.php\/ToSC\/article\/view\/9332"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,12,3]]},"references-count":0,"URL":"https:\/\/doi.org\/10.46586\/tosc.v2021.i4.138-176","relation":{},"ISSN":["2519-173X"],"issn-type":[{"value":"2519-173X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,12,3]]}}}