I guess as long as Betcoin verifies both sites, it should be ok. IMO in theory the best way would be this: make a "secret" word + your pick of the winner, then make a SHA512 of it. Post this before the game. After the game you post the "secret" so people can verify your pick, without knowing your pick in advance. Provably fair World Cup promotion But this might be too hard for some (actually there are online SHA512 generators, so this is really easy.) For example:

Post in advance:
BBB3DD45C01A91B2B724A6DC94DD304053918414F6CBB6B1EAAD7A371EABEC7C608FA66020A1711 C22621B1C704851BB3ADBF967945CA8BA6686F7274CA69A07

Afterwards:
gdq345gzfsGFDS45-IRAN

So my pick was "iran" and you can put "gdq345gzfsGFDS45-IRAN" in the online SHA512 generator to see the hash matches.



Also btw, Live betting is not allowed to get points right? Just saying before someone finds that as another trick to bet on a team as soon as they score etc. That would be bit easy to get points :p