Thank you for the suggestion, it is something along the lines of what I was planning to do. I was looking for a way to do this without having to store 70-80 million ticket hashes every round due to the load it would put on our servers, but it doesn't seem like there is another way.
The method is pretty good, bit it still doesn't solve the problem of me cheating by creating fake accounts and tickets for them so that the hashes of these tickets fall into the positions of the winning numbers. I doubt there is any way to make the lottery 100% provably fair due to this but this is still a much better implementation that what we currently have.
I'll add this to my to-do list and should be implemented in a month I hope.
Please pm me your freebitco.in user id for a bonus
Maybe increase the price of each ticket by 10 times (to 0.00075 USD worth)? The free tickets given away in free rolls could be changed to given away by chance (e.g. if rolled lower than 2000/greater than 8000 than give 1 ticket). Assuming 100 byte per ticket data, 7M tickets would be only 700MB in size.The method is pretty good, bit it still doesn't solve the problem of me cheating by creating fake accounts and tickets for them so that the hashes of these tickets fall into the positions of the winning numbers. I doubt there is any way to make the lottery 100% provably fair due to this but this is still a much better implementation that what we currently have.
I'll add this to my to-do list and should be implemented in a month I hope.
Please pm me your freebitco.in user id for a bonus
Or make the lottery blockchain-based: Order the tickets by some method (maybe the order of users acquired them, or by user ID), and make use of a block hash (use the last digits, the first digits is always 0) to determine the winners.
P.S. Why not make freedoge.co.in have these features too?
The main problem is what wetsuit pointed out already. He can make bunch of fake accounts and assign them another 70 mil tickets providing him 50% chance the winner will be one of those. I think there is no way how to make this 100% provably fair other than using third party to assign and check the ticked fairness.
There would have to be a completely different way of tickets distribution. Something like every ticket to be hash of data linked to account (where the ticket come from: bought, hi-lo game, freeroll, ref. hi-lo ... ) and all these data would have to be public. I guess this is impracticable.
To eliminate fake account creation would require complete user identity reveal and again to publish them (the IDs, names, phone nrs.) so everyone can check ... this is even more impracticable/unacceptable.
I run out relevant options but glad we have open a discussion because solving this issue would make the site much more attractive ... perhaps some user will find a brilliant solution how to.