Hi I have been interested in the puzzle for several months and after months of scanning and learning I found a site that seems to have scanned all the range' in #64 puzzle's keyspace (from 2^63 till 2^64-1 decimal, 0x8000 0000 0000 0000 - 0xFFFF FFFF FFFF FFFF) and he find nothing.https://hashkeys.club/64/.
How is possible? Sorry for google translate.
 Can someone explain to me!