Streebog

Streebog is a cryptographic hash function defined in the Russian national standard GOST R 34.11-2012, which is also published as RFC 6986 and included in the international standard ISO/IEC 10118-3. It was created to replace the obsolete hash function of the earlier GOST R 34.11-94 standard. Streebog processes its input in 512-bit blocks and uses the Merkle-Damgard construction to handle messages of any length. Its compression function works in Miyaguchi-Preneel mode and relies on a 12-round cipher with a 512-bit block and key that resembles AES but operates on an 8 by 8 matrix of bytes. A shorter Streebog-256 variant uses a different initial state and truncates the output. The name comes from Stribog, a god of wind in Slavic mythology. A Russian committee opened a public cryptanalysis competition in 2013, and later researchers published attacks on reduced-round versions and criticised the origin of its substitution box.