Okay, so I can see in the HTTP requests that you send a new proper-random clientseed every bet now. But there are still some things missing. I guess some of that I should have previously mentioned and emphasized (although RHavar did mention some of it in a reply.) Anyway.. it might be best if I just describe what I think would be the best provably fair system for a MP app. Probably more MP apps could use this This might get a bit long..

Note that almost all provably fair implementations, even on biggest non-MP sites like Primedice, could be improved in my personal opinion. So I don't think it's easy to get all the details right, but still fundamentally there are things missing now on BB. Obviously some of these things take more time than the "1 minute fix" that I mentioned But still I think it's worth it to take some time to fix it properly.

The thing I like about MP (with regards to provably fair), is that it allows app/sites to "protect" their players against MP. Because in the end, only MP can cheat the players if the provably fair mechanism is bad. But if you as a MP app actively verify all bets, it gives the provably fair mechanism an advantage compared to non-MP sites. Because if you do that, it would need some serious scammy colluding between MP and app owner to cheat the players. However, this only works if the implementation is good.