Streebog

Streebog is a family of two hash functions, Streebog-256 and Streebog-512, that produce output 256-bit or 512-bit hash respectively from a bit string of arbitrary size using the Merkle–Damgård construction. The high-level structure of the new hash function resembles the one from GOST R 34.11-94, however, the compression function was changed significantly. The compression function operates in Miyaguchi–Preneel mode and employs a 12-round AES-like cipher.

The function was named Streebog after Stribog, the god of rash wind in ancient Slavic mythology,

Examples of Streebog hashes

Hash values of empty string.

Streebog-256("")
0x 3f539a213e97c802cc229d474c6aa32a825a360b2a933a949fd925208d9ce1bb
Streebog-512("")
0x 8e945da209aa869f0455928529bcae4679e9873ab707b55315f56ceb98bef0a7 \
362f715528356ee83cda5f2aac4c6ad2ba3a715c1bcd81cb8e9f90bf4c1c1a8a

Even a small change in the message will (with overwhelming probability) result in a mostly different hash, due to the avalanche effect. For example, adding a period to the end of the sentence:

Streebog-256("The quick brown fox jumps over the lazy dog")
0x 3e7dea7f2384b6c5a3d0e24aaa29c05e89ddd762145030ec22c71a6db8b2c1f4
Streebog-256("The quick brown fox jumps over the lazy dog.")
0x 36816a824dcbe7d6171aa58500741f2ea2757ae2e1784ab72c5c3c6c198d71da
Streebog-512("The quick brown fox jumps over the lazy dog")
0x d2b793a0bb6cb5904828b5b6dcfb443bb8f33efc06ad09368878ae4cdc8245b9 \
7e60802469bed1e7c21a64ff0b179a6a1e0bb74d92965450a0adab69162c00fe
Streebog-512("The quick brown fox jumps over the lazy dog.")
0x fe0c42f267d921f940faa72bd9fcf84f9f1bd7e9d055e9816e4c2ace1ec83be8 \
2d2957cd59b86e123d8f5adee80b3ca08a017599a9fc1a14d940cf87c77df070

Cryptanalysis

In 2013 the Russian Technical Committee for Standardization "Cryptography and Security Mechanisms" (TC 26) with the participation of Academy of Cryptography of the Russian Federation declared an open competition for cryptanalysis of Streebog hash function, which attracted the international attention to the function.

Ma, et al, describe a preimage attack that takes 2⁴⁹⁶ time and 2⁶⁴ memory or 2⁵⁰⁴ time and 2¹¹ memory to find a single preimage of GOST-512 reduced to 6 rounds. They also describe a collision attack with 2¹⁸¹ time complexity and 2⁶⁴ memory requirement in the same paper.

Guo, et al, describe a second preimage attack on full Streebog-512 with total time complexity equivalent to 2²⁶⁶ compression function evaluations, if the message has more than 2²⁵⁹ blocks.

AlTawy and Youssef published an attack to a modified version of Streebog with different round constants. While this attack may not have a direct impact on the security of the original Streebog hash function, it raised a question about the origin of the used parameters in the function. The designers published a paper explaining that these are pseudorandom constants generated with Streebog-like hash function, provided with 12 different natural language input messages.

AlTawy, et al, found 5-round free-start collision and a 7.75 free-start near collision for the internal cipher with complexities 2⁸ and 2⁴⁰, respectively, as well as attacks on the compression function with 7.75 round semi free-start collision with time complexity 2¹⁸⁴ and memory complexity 2⁸, 8.75 and 9.75 round semi free-start near collisions with time complexities 2¹²⁰ and 2¹⁹⁶, respectively.

Wang, et al, describe a collision attack on the compression function reduced to 9.5 rounds with 2¹⁷⁶ time complexity and 2¹²⁸ memory complexity.

See also

• Hash function security summary

Source

http://wikipedia.org/