Paper 2021/292
Quantum Collision Attacks on Reduced SHA-256 and SHA-512
Akinori Hosoyamada and Yu Sasaki
Abstract
In this paper, we for the first time show dedicated quantum collision attacks on SHA-256 and SHA-512. The attacks reach 38 and 39 steps, respectively, which significantly improve the classical attacks for 31 and 27 steps. Both attacks adopt the framework of the previous work that converts many semi-free-start collisions into a 2-block collision, and are faster than the generic attack in the cost metric of time-space tradeoff. We observe that the number of required semi-free-start collisions can be reduced in the quantum setting, which allows us to convert the previous classical 38 and 39 step semi-free-start collisions into a collision. The idea behind our attacks is simple and will also be applicable to other cryptographic hash functions.
Metadata
- Available format(s)
- Category
- Secret-key cryptography
- Publication info
- Preprint. MINOR revision.
- Keywords
- hash functionSHA-256SHA-512collision attackquantum attackconversion from semi-free-start collisions
- Contact author(s)
- akinori hosoyamada bh @ hco ntt co jp
- History
- 2021-06-25: revised
- 2021-03-07: received
- See all versions
- Short URL
- https://ia.cr/2021/292
- License
-
CC BY