Related-key attack on 5-round Kuznyechik

The first related-key attack on 3-round (of 9) Kuznyechik with 2-round (of 8) key schedule was presented in CTCrypt'18. This article describes a related-key attack on 5-round cipher with the same key schedule. The presented attack also has a practical complexity (2$^{32}$ operations, 2$^{30}$ memory, 2$^{16}$ related keys, one chosen plaintext-ciphertext pair for each key) and was verified in practice. Our results was obtained due to the simultaneous use of the integral properties of the cipher transformations and the key schedule.