What would be the most transparent way to show a fair shuffle literally possible?

Question

I want to make an ios app, for fun to improve my dev skills, to do what no other app/poker site has done and be completely transparent.

I just want to match casinos shuffling as imperfect as that may be, no quantum, no true shuffle, no blockchain shuffle, no user input mouse movements being integrated, all that equates to horrible experiences over several sites, juiced boards for action and rake to keep the gambling addicts getting their 'thrills' and coming back for more, but this isn't a whine thread it's an advice thread.

There are source codes on github but that's not good enough, coin pokers code is on github, go play some freerolls on coinpoker see how legit they feel, same bs. It's Tony G, and virtue poker is phil ivey, he tried to cheat a casino, these are not people with great trustability, fancy blockchain decentralized mumbo jumbo copy or not.

so tldr, can I display the rng code in real time as the hand shuffles or something, to be verified later, something infallably provable that no other site would ever dare?

Answer 1

Doing this and protecting the integrity of your game at the same time is not an easy problem to solve. If you surface everything you do to the players on the site and use your own sources of randomness that is also surfaced, players may be able to predict what your source of randomness will generate and therefore predict the shuffle of the deck.

I would recommend that you use a free, accredited source of randomness that is proven to be as close as possible to purely random. Use the hash or whatever this rng produces and make your own algorithm to predictably generate a shuffle of the deck. You can surface the hash and your algorithm to the players and they can plug it in themselves and see it spit out the shuffle that they had in the hand. If they have questions about how random the rng is, they can be referred to the source that you use.

As a side note, big poker sites have very little incentive to not use a good source of randomness and randomly generate their shuffles each time. They have a large amount of users and make a lot of money operating with good random shuffles. If a big poker site like this (especially a regulated one) were to be caught using anything but a random shuffle, they would lose any licenses they have to operate if they are regulated and users would move away from the site.

Answer 2

One possibility:

Take the shuffled deck, add a timestamp, create a cryptographic hash of it. Record both on your site. Display the hash during the hand. Honestly, since you can create the deck after all players are in the hand, the deck file can include player names/positions as well and therefore have hole/burn/board cards marked.

After the hand, you can download the deck file from the site and run it through the same crypto algorithm to validate that the hash displayed at the time matches.

By doing a hash, there's nothing to "decrypt", so you don't have to worry about someone deciphering the deck from the hash.

That said, if I suspected a site of doing funny business, it wouldn't really be the deck that I worried about. It would be if insiders had access to things like the deck and other player hole cards. That can't just be validated with a code.

ETA: One other thing might be possible. Since you can still manipulate which deck is generated for each hand, maybe you could instead create "blocks" of decks. Shuffle (for example) 10 or 100 decks at a time. Then the same code shown would be shown during play of all of those decks. After the block is used, you could have a link on the site that showed the N (consecutive) games that were played with that block. That would potentially give greater confidence that the decks aren't being chosen to aid a particular table.

Answer 3

A fair shuffle is a true random shuffle. Period. Whatever "bad experiences" you attribute to mathematically perfect shuffles are either users not knowing what they are talking about or the site not being as truly random as it claims. Simulating a physical casino shuffle is nonsense.

There is a method for transparently generating a random shuffle among several players. It's basically this: before the hand, publish to every player (and the world) exactly what algorithm you will use to generate a random sequence, how that sequence will be used to choose cards, and a random seed. Then each player generates a random seed of their own and sends it to you in secret. You then combine your first seed, another random seed that you choose, and each of the players seeds together, and use that to seed the RNG that chooses cards. After the hand, you publish all the seeds and players can verify that their seed was used and that the sequence was generated properly.

Answer 4

Your on the right track. I am a little knowledgeable but no great expert just to be clear. Awhile back I did some research to gain some understanding of the whole subject. (I had written a keno game that was repeating broads every so often, easy stuff to screw up).

If your code depends on secrecy then it is inherently insecure. This just means that everything you know about your keys anybody can know and your program is still secure. So you should be able to be totally transparent with your program and it should be secure. You should be able to give details about how you came up with your key/seed, the size of your key and all the details about the RNG your using. (Online poker rooms like you said are not very transparent with their shuffle routines, it is one of the minor reasons that I do not play online for the past 15 years. Major one BTW is because they have no shot at stopping collusion.)

I found out a couple of general things about seeds/keys and (P)RNG's. First is that there are different types of RNG's, generally two types, one type is designed with security in mind, the other type with true random number generation in mind. Basically some are better at generating keys securely for transactions, and others are better for simulation. So coming up with the best RNG for a poker game is rather the challenge because one needs transactional security as well as true randomness for the shuffle. "Do all" things are rarely really good at doing anything (think Swiss Army knife). Around 2004 UB was the victim of a hack that was out there for awhile that was able to break their security. The hacker was selling it for something like 32K a copy, pretty good money for a 16 year old kid.

Wish I could give you more. If I was betting on what your thinking it would be "tell me something I don't know." It was over a decade ago that I surveyed the subject. So I don't have any suggestions as far as specific RNG's go for poker.