Kalyna (cipher)

Kalyna (Ukrainian: Калина, Viburnum opulus) is a symmetric block cipher. It supports block sizes of 128, 256 or 512 bits; the key length is either equal to or double the block size.

Kalyna was adopted as the national encryption standard of Ukraine in 2015 (standard DSTU 7624:2014) after holding Ukrainian national cryptographic competition. Kalyna is a substitution–permutation network and its design is based on the Rijndael (AES) encryption function having quite different key schedule, another set of four different S-boxes and increased MDS matrix size.

Kalyna has 10 rounds for 128-bit keys, 14 rounds for 256-bit keys and 18 rounds for 512-bit keys. Independent researchers proposed some attacks on reduced-round variants of Kalyna, but all of them have a very high complexity and none of them are practical.