At the beginning of every week, all the rolls that will be played for the whole week are randomly pre-calculated and written to a text file. The text in the text file is kept secret for the rest of the week, but the hash is publicly published (and this weeks hash is
....) Bets are processed in the order they come in, and assigned a sequential number (which is visible in comments made for winning hands.) At the end of the week, the text from the text file is published, and everyone can see the order of rolls. The public hash is proof that the order and value of bets in the text file has not been modified since the wager was made (the smallest of changes to the text file would result in a completely different hash value.) By inspecting the block chain it can be seen the rolls correspond correctly to those presented in the text file. This proves beyond doubt that the bets are fair.