The paper “Back to the Past: Backward Resampling Method with Applications to CHCTR2 and CLRW2” has been accepted at the Asiacrypt 2026 conference. Asiacrypt is the IACR’s annual flagship conference for the Asia-Pacific region, Asiacrypt 2026 will be held in Hong Kong.
In light of NIST’s ongoing accordion standardization efforts, this paper propose the backward resampling method, and uses it to improve the multi-user security bounds of the CHCTR2 and CLRW2 block-cipher-based accordions.
It is co-authored by Yusuke Naito, Yu Sasaki, Takeshi Sugawara, Yu Long Chen, Yukihito Hiraga, and Nicky Mouha (Founder of KeyCryptic).