Improved conditional cube attacks on Ascon AEADs in nonce-respecting settings with a break-fix strategy
The best-known distinguisher on 7-round Ascon-128 and Ascon-128a AEAD uses a 60-dimensional cube where the nonce bits are set to be equal in the third and fourth rows of the Ascon state during initialization (Rohit et al. ToSC 2021/1). It was not known how to use this distinguisher to mount key-reco...
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
2024
|
| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/181761 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | The best-known distinguisher on 7-round Ascon-128 and Ascon-128a AEAD uses a 60-dimensional cube where the nonce bits are set to be equal in the third and fourth rows of the Ascon state during initialization (Rohit et al. ToSC 2021/1). It was not known how to use this distinguisher to mount key-recovery attacks. In this paper, we investigate this problem using a new strategy called break-fix for the conditional cube attack. The idea is to introduce slightly-modified cubes which increase the degrees of 7-round output bits to be more than 59 (break phase) and then find key conditions which can bring the degree back to 59 (fix phase). Using this idea, key-recovery attacks on 7-round Ascon-128, Ascon-128a and Ascon-80pq are proposed. The attacks have better time/memory complexities than the existing attacks, and in some cases improve the weak-key attacks as well. |
|---|