Chapter

Fast Software Encryption

Volume 5086 of the series Lecture Notes in Computer Science pp 224-234

A (Second) Preimage Attack on the GOST Hash Function

  • Florian MendelAffiliated withInstitute for Applied Information Processing and Communications (IAIK), Graz University of Technology
  • , Norbert PramstallerAffiliated withInstitute for Applied Information Processing and Communications (IAIK), Graz University of Technology
  • , Christian RechbergerAffiliated withInstitute for Applied Information Processing and Communications (IAIK), Graz University of Technology

Abstract

In this article, we analyze the security of the GOST hash function with respect to (second) preimage resistance. The GOST hash function, defined in the Russian standard GOST-R 34.11-94, is an iterated hash function producing a 256-bit hash value. As opposed to most commonly used hash functions such as MD5 and SHA-1, the GOST hash function defines, in addition to the common iterated structure, a checksum computed over all input message blocks. This checksum is then part of the final hash value computation. For this hash function, we show how to construct second preimages and preimages with a complexity of about 2225 compression function evaluations and a memory requirement of about 238 bytes.

First, we show how to construct a pseudo-preimage for the compression function of GOST based on its structural properties. Second, this pseudo-preimage attack on the compression function is extended to a (second) preimage attack on the GOST hash function. The extension is possible by combining a multicollision attack and a meet-in-the-middle attack on the checksum.

Keywords

cryptanalysis hash functions preimage attack