Paper 2018/1122
Improved Quantum Multicollision-Finding Algorithm
Akinori Hosoyamada and Yu Sasaki and Seiichiro Tani and Keita Xagawa
Abstract
The current paper improves the number of queries of the previous quantum multi-collision finding algorithms presented by Hosoyamada et al.~at Asiacrypt 2017. Let an $l$-collision be a tuple of $l$ distinct inputs that result in the same output of a target function. The previous algorithm finds $l$-collisions by recursively calling the algorithm for finding $(l-1)$-collisions, and it achieves the query complexity of $O(N^{(3^{l-1}-1) / (2 \cdot 3^{l-1})})$. The new algorithm removes the redundancy of the previous recursive algorithm so that different recursive calls can share a part of computations. The new algorithm achieves the query complexity of $O(N^{(2^{l-1}-1) / (2^{l}-1)})$. Moreover, it finds multiclaws for random functions, which are harder to find than multicollisions.
Metadata
- Available format(s)
- Category
- Foundations
- Publication info
- Preprint. MINOR revision.
- Keywords
- post-quantum cryptographyquantum algorithmmulticlawmulticollision
- Contact author(s)
- hosoyamada akinori @ lab ntt co jp
- History
- 2019-01-28: last of 6 revisions
- 2018-11-20: received
- See all versions
- Short URL
- https://ia.cr/2018/1122
- License
-
CC BY