[knot-dns-users] DS record digest

Hi, can someone please give me any explanation (or command) how my domain registrator got from this record what i give him: liberland.cz. 3600 DNSKEY 257 3 13 ei9T3egqng+nlAHeNfF6BzggGCyvS2lU5ih2BZuvkzFGxkBdUJ0blgSiW5iYIROvAEHQv5Ls3sNPA9JIt8iRjg== this record: liberland.cz. 17999 IN DS 21107 13 2 9405F3324FDCE3F0CC4E5D94CBFB5D8A4F211E3010D447B5FD73765F9EEC20EB ??? I want sign child zones but I can't find where i get hash ,,9405F3324FDCE3F0CC4E5D94CBFB5D8A4F211E3010D447B5FD73765F9EEC20EB" And algorithm in RFC: https://tools.ietf.org/html/rfc4034#section-5.4 digest = digest_algorithm( DNSKEY owner name | DNSKEY RDATA); "|" denotes concatenation DNSKEY RDATA = Flags | Protocol | Algorithm | Public Key. doesn't help me :-/ Thanks and regards, Jakub