## Cryptology ePrint Archive: Report 2009/407

Single Block Attacks and Statistical Tests on CubeHash

Benjamin Bloom and Alan Kaminsky

Abstract: This paper describes a second preimage attack on the CubeHash cryptographic one-way hash function. The attack finds a second preimage in less time than brute force search for these CubeHash variants: CubeHash $r$/$b$-224 for $b > 100$; CubeHash$r$/$b$-256 for $b > 96$; CubeHash$r$/$b$-384 for $b > 80$; and CubeHash$r$/$b$-512 for $b > 64$. However, the attack does not break the CubeHash variants recommended for SHA-3. The attack requires minimal memory and can be performed in a massively parallel fashion. This paper also describes several statistical randomness tests on CubeHash. The tests were unable to disprove the hypothesis that CubeHash behaves as a random mapping. These results support CubeHash's viability as a secure cryptographic hash function.

Category / Keywords: secret-key cryptography / hash functions, CubeHash, cryptanalysis, statistical randomness tests