Which Bitcoin-powered gambling sites are "provably fair"? Through the spread of Bitcoin for the purposes of online gambling, the concept of "provably fair" games came more into the limelight. Which of the Bitcoin-powered gambling websites are provably fair?

For clarity's sake, a provably fair game is a game that uses cryptographic algorithms to ensure their players that the game host or other players did not temper with the outcome of the game after it has begun.
BitLotto was likely the first blockchain-based "provably fair".  It uses the transaction ID as the "ticket", and the results of a large government-run lottery to determine the winning numbers.


http://www.BitLotto.com


SatoshiDICE became a blockbuster (pun intended) method for online gambling.  It uses the transaction ID to determine the "lucky number" (between 0 and 65,535).  The secret used for determining that lucky number is revealed after the end of the day.


http://www.SatoshiDICE.com


bitZino gets credit for coining the term "provably fair", and first launched an online blackjack game then followed it up first with video poker and then roulette as well.  The game allows the user to change the client seed used for each play.


http://www.bitZino.com


BitJack21 was possibly the first.  The game gives the ability for the player to change the seed used for each hand.


http://bitjack21.com/


BitDice.com, SatoshiRoulette.com and others claim to be provably fair, I believe.  But I haven't gone through the verification steps myself to confirm.

BitLotto and SatoshiDICE wagers can be verified by anyone at any time after the results are published in BitLotto's instance, and after each day's secret is published for SatsoshiDICE's instance.  Proving that bitZino always computed the results correctly requires logging of the hash, the client seed, and also the way the hand was played -- so it is much more effort to verify unless there is automation but no automated solutions for verifying all wagers on bitZino have been made available.

Here's an article on what provably fair means:


http://www.forbes.com/sites/jonmatonis/2012/08/31/bitzino-and-the-dawn-of-provably-fair-casino-gaming


Here is one explaining how it works:


http://bitcoinreviewer.com/provably-fair/


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Additional sites in which claim to be provably fair but I've not gone to verify:


http://www.satoshibet.com
http://www.BitMillions.com  (Apparently uses as a seed a Twitter sequence?)
http://www.KingCo.in 
http://www.BitcoinVideoCasino.com 
http://www.Playt.in
http://www.bitino.com
http://www.pinballcoin.com
http://www.blockchainroulette.com
http://www.diceoncrack.com   (Uses transaction hash just like SatoshiDICE, so should be easily to verify)


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