Abstract
Recent developments in the field of cryptanalysis of hash functions has inspired NIST to announce a competition for selecting a new cryptographic hash function to join the SHA family of standards. One of the 14 second-round candidates was CubeHash designed by Daniel J. Bernstein. CubeHash is a unique hash function in the sense that it does not iterate a common compression function, and offers a structure which resembles a sponge function, even though it is not exactly a sponge function.
In this paper we analyze reduced-round variants of CubeHash where the adversary controls the full 1024-bit input to reduced-round CubeHash and can observe its full output. We show that linear approximations with high biases exist in reduced-round variants. For example, we present an 11-round linear approximation with bias of 2 235, which allows distinguishing 11-round CubeHash using about 2470 queries. We also discuss the extension of this distinguisher to 12 rounds using message modification techniques. Finally, we present a linear distinguisher for 14-round CubeHash which uses about 2812 queries.
In this paper we analyze reduced-round variants of CubeHash where the adversary controls the full 1024-bit input to reduced-round CubeHash and can observe its full output. We show that linear approximations with high biases exist in reduced-round variants. For example, we present an 11-round linear approximation with bias of 2 235, which allows distinguishing 11-round CubeHash using about 2470 queries. We also discuss the extension of this distinguisher to 12 rounds using message modification techniques. Finally, we present a linear distinguisher for 14-round CubeHash which uses about 2812 queries.
| Original language | English |
|---|---|
| Title of host publication | International Conference on Applied Cryptography and Network Security |
| Editors | J. Lopez, G. Tsudik |
| Place of Publication | Berlin |
| Publisher | Springer |
| Pages | 462-478 |
| Number of pages | 17 |
| ISBN (Electronic) | 978-3-642-21554-4 |
| ISBN (Print) | 978-3-642-21553-7 |
| DOIs | |
| Publication status | Published - 2011 |
| Externally published | Yes |
| Event | Applied Cryptography and Network Security - 9th International Conference - Nerja, Spain Duration: 7 Jun 2011 → 10 Jun 2011 Conference number: 2011 |
Publication series
| Name | Lecture Notes in Computer Science |
|---|---|
| Publisher | SpringerLink |
| Volume | 6715 |
Conference
| Conference | Applied Cryptography and Network Security - 9th International Conference |
|---|---|
| Abbreviated title | ACNS |
| Country/Territory | Spain |
| City | Nerja |
| Period | 7/06/11 → 10/06/11 |
Keywords
- CubeHash
- SHA-3 competition
- Linear cryptanalysis