Bitcoin Forum

Starting next week the crypto gambling foundation (www.cryptogambling.org) will be publicly disclosing sites which don't use proper provably fair methods.

The proper way of creating a true provably fair website consists of 3 simple aspects.


A lot of websites miss the nonce aspect. This in turn creates an unfair environment and a major opportunity to rig events. Unless the user changes their client seed EVERY round this case is not fair. They will also have to in turn engage users to verify bets one by one to ensure their fairness. This isn't what anyone (Lets be realistic) does and leaves the vast majority of people open to being scammed. If an operator notices you are not changing your client seed EVERY bet they are able to change the outcome of rolls.

To the websites which do implement fairness properly, this is not fair and leaves Bitcoin gamblers vulnerable.

If you an operator and wish to learn how to implement a proper provably fair system feel free to add me on Telegram (@EdMiroslav).

By all means if we call your fairness system out, we are not saying you are scamming; we're saying you need to improve your system to ensure that's no longer an opportunity.
 

Suggestion from Rhaver (Apart of the CGF) which is a very fair way of going about this situation.

Sounds fair, best of luck with helping improve Bitcoin. I'm really loving the whole initiative from the Gaming Foundation. You guys rock. Just don't get power hungry..

Likewise. Who's currently on the board? Looking forward to seeing more from you guys.

Very good idea and attitude! thats the way to go

By the looks of it Stunna and Edward (Aengus?) are running it

It looks like Bustabit is also involved. The 4 (Primedice, Bustabit, Stake & Bustadice) biggest provably fair gaming sites...

Correct!

And thanks JackpotRacer! Looking forward to having your site inline with the fairness one day. I can help you with that if you like.

@Aengus thx for the kind words and offer to help. I will for sure contact you to check us out and to help if we will need it

we are glad that finally someone is trying to take care of Provably Fair casinos

I mean this is a pretty good idea but wouldn't having a client-side seed generator also fix the problem with getting a new hash each round? Because the client seed gets changed each round.

Not exactly as code can be injected/manipulated for individual users

I never knew that there are some sites faking the provable fair script. What about freebitco.in I love thier website but this seems rigning a bell now why I am always getting loss to them.

Unless ofcourse, the one managing the site & the one managing the actual bets are different entities :>

You appear to have said "by all means" when you mean "by no means" in the op.

This has been a long time coming. This should have been here for a long time. A board that would review provably fair system must be implemented since I also believe that 99% of all players do not even know how this works. Hence, they are ignorant of the fact that it should be like this. I also see a lot of casino sites that say they are provably fair and they place that logo on their site, but they don't even have a way to verify their bets.

This will be a great change to the crypto gambling scene!

If you are talking about their multiplier than you will never win any significant amount there because of high house edge (5%) usually bitcoin dice site only have 1% or even less than that H.E.

Thanks for coming up with this foundation, I haven't thought that site can detect the client seed, isn't that generated randomly on browser/client side  ??? ::)

Yeah bustabit owner is one of the really genius guy in gambling world of crypto also quite helpful to others, I have seen him pointing out different bugs in gambling sites before. He and primedice/stake guys must be behind this great concept. Bustadice also runs on almost same script of bustabit and bustadice owner also have some ownership in it.

 Nice! This is a great idea and one in my opinion that is long overdue. Not only does it prove legitimacy for more established casinos, I could also see if the detering new casinos that are not using the proper provably fair system. Really looking forward to this project, keep up the good work guys.

Nice initiate ! It again depends why would someone take your words seriously ? Would you be negotiating with the gambling websites to show those websites are legit thereby getting paid from them or this is just another quick money making gimmick ? Lots of possibilities.

Unless your estimation involves math and logic I wouldn't take your seriously.

I appreciate your effort to call out sites which don't use proper provably fair methods, but I also suggest to disclose sites that false and misleading claim to have a valid license!

Because to play at a site with provably fair system but fake license will not help you much if they simply close your account and victims look for help from their fake licensor.

the title at first made me wonder about what this will be , then I saw the other topic by Stunna
great move and hopefully it will spread awareness and help the community here , I guess some dice sites may start losing players like luckygames after their last cheat

I think it's a bit too harsh to call it "fake" provably fair, as without a nonce it is still provably fair -- just perhaps suboptimal from a users point of view. But if you trust the client (e.g. you've audited a static version, or using some 3rd party client you trust) it's actually possibly better.


There have been a bunch of casinos though with "fake provably fair", the biggest offender I remember was the old 999dice which put a "betId" (instead of a nonce) in the preimage, which allowed them to 100% control the outcome. And then there's been dozens of sites with "fake" provably fair systems (pretty much 99% of all multiplayer gambling games that come out, they screw up the provably fair and it's not actually provably fair).


I would be trying to categorize sites (from best to worst):

* Trustless
* Provably fair  (follows best practices)
* Provably fair (warning: suboptimal, not practical for human verification)
* Not Provably Fair   (game design makes provably fair impractical)
* Not Provably Fair   (for no good reason)
* Fake Provably Fair  (claims to be provably fair, but isn't)

Completely agree. Will be adding this quote to OP.

"suboptimal from a users point" if you mean with users the players of a casino IMO the players should not need to trust any casino OP and need to be sure that they cant be cheated. if this kind of Provably Fair exists and if this is the "nonce" version it should be implemented by all casino OPs

a player who wins will in general not take his time to verify his bets after his gambling session but if a player loses he will yes try  to verify his session

just my 2 satoshi

Awesome that your on board Rhaver, you're one of the smartest guys in the Bitcoin gambling community. I hope to see you develop this.

Rhaver is the king of gambling, behind dooglus of course. Maybe stunna too if he's lucky :p

Thank you for all the support from everyone.

So in short what the service propose to offer is providing a review on gambling sites. We can only hope that you won't compromised along the line because there are several sites that claim to review but the same gambling sites they want to provide unfettered review about, have their banner on their site as a form of advertisement.

My advice, when you discover a site that does not comply based on your calculations, the first is to contact them because they might have built some valid assumptions into their own calculations so as to avoid issues of going back and forth on the basis of figures which does not add any value.

You are saying that some sites don't have the nonce when calculating the provably fair outcome

[Server Seed Hash] + [Client Seed] + [Nonce]

However if its just the server seed hash and client seed, and if both of those are constant won't the roll be exactly the same everytime.

In this case I assume the server seed hash keeps changing, while client seed stays the same. In that case since the noonce always starts at 1, won't it be exactly the same situation.

Since the casino already knows what the nonce will be and they know their server seed. And they assume "client seed" won't get changed.

Despite my own personal feelings that people should do their own research, can't deny that a lot of newbies wouldn't know how to verify provably fair claims on their own, based on my own initial experience with crypto casinos. On that note, I think this is a good call and can be educational at the same time.

Just be careful not to harm your own reputation also. Rhavar's right that it would be harsh (not to mention unfair) if a blanket label of fake be used in calling sites out. Might want to edit the thread title to better reflect your objectives... which is not to call out fake sites but perhaps... to ensure a standard or benchmarking for Provably Fair casinos?

I'd advise to develop a standard operating procedure for approaching, informing and evaluating site owners responses and (possible) rectifications before announcing anything. I think owners should also be given the benefit of doubt - a proper reach out can help establish this.

Moment you change the client seed (Yourself and not through sites choice) you have made the decision of what all the next outcomes will be. This is due to an added nonce. If you don't have the nonce you are forced to change your client seed every single time.

Updates on current members can be found on the forum. Welcome Betking as a new member. They have been a trust machine in the Bitcointalk community for years & we can't stress enough about the safety of betting there. Rest assured, your results are random & your funds safe.

Great job with their recent ICO. I can't wait to see them add more provably fair casino games!

Finally got this explanation about provably fair, thank you. I will pay attention to this topic read it in depth mode :).

I second you and very well expressed.

Glad we're getting the message across nice & simply!

Welp, I think it's a good idea to do this. however I don't think someone who owns a gambling site should be thebone doing this as he/she might be biased.

biased to what?

Good job, Now you want to  stop them from cheating people? I used to gamble a lot but after some time I realized the only outcome was for me to lose no matter how I gambled and how many strategies I used. I wanna know what happens to casinos if they all use real provably fair system? Probably they will all close down their business and go home, Because if you let the results to be determined by random outcomes then one would use a simple strategy to win at the end.

I agree...
This is the same as Marlboro establishing foundation "Let's stop lung cancer"  ;D

That's just definition of Conflict of interests: https://en.wikipedia.org/wiki/Conflict_of_interest

sorry but I cant agree with this comparison. lets say primedice is using the perfect Provably Fair solution and asking all casinos to add the same perfect Provably Fair solution what would be wrong with this or biased?

how many perfect Provably Fair solutions are out there?

to be frank I am not an expert of PF but I always wanted to see that the PF solution is done the way that a player can verify his bets after his session and it should not matter if the player's session was 1 bet or thousands of bets or more. to change client seed for each bet is not good for players and is not good for casino OPs

In that case you are not forced to change your client seed, most likely in that scenario the server seed would change everytime.

Basically its how the site is coded, but it makes no difference whether a nonce is incremented or the server/client seed is changed.

Someone did an analysis of this and tried to find a pattern, and the results were all "almost" equallity likely.

What are you talking about ? what is a provably fair site ?

Biased about their own site.
Who knows, maybe in the future an even better PF system could come out. Being unbiased in that situation is so much better for the rest. Also if you do this while owning a site yourself, it could be seen as just bashing on competition trying to get others out of the game in an underhanded method. So I still think it's better if someone without any affiliation to any site does this.

Hey guys,

First of all, we are happy to join the CGF.

Secondly, I would like to say that


Is not absolutely true. For example, BitDice does not have [Nonce] part, we show [Server Seed Hash] prior the bet, generate random [Client Seed] on the client and show the [Server Seed] after the bet.

http://prntscr.com/h4pi2f

This method gives few advantages:

1) If the server was compromised hacker can get an advantage over only 1 next bet. ( This prevents the case that happened with PD )
2) The casino doesn't know about future player outcomes.

Regards,
Alex.

This is a great categorization RHavar.
It helps a lot to distinguish the nuance!

good to see more and more joining in

to be frank I am not a Provably Fair expert. my question to you is if the player can verify thousands or more bets after his betting session? or is it only bet after bet after bet that he can verify?

thx

You guys are doing a great initiative here.
Well done!
As someone in gambling since 1999 and crypto gambling since 2013 I totally get the need for this.
I'd like to suggest than an education aspect here is key too.
In my experience the reason provably fair has not gotten the traction it could is because players do not understand it.
It woould be good for all the brands if more people understood the benefit.

Not sure if you're trolling, but just in case some people don't know how this works, that's not at all how that works. Casinos wouldn't close down if they were probably fair. "Provably fair" does not mean you won't lose money. It means you know exactly what the odds are, and since you're betting against the house, you know the odds are against you by 1-2%. Provable fairness doesn't stop you from losing money, it stops the house from changing the odds against you in a way you weren't expecting.

You're still playing a game where you're expected to lose money to the house in the long run. That's gambling.

The forum  { https://forum.cryptogambling.org/ } is still very quite, I would have thought that there would have been a lot

more activity for a important need like this. I hope whomever is affiliated with this, would be properly screened, because only

one mistake will kill this initiative. People are already paranoid about these sites that are "ranking" gambling sites.  ???

Your method is absolutely provably fair, and certainly does have advantages (like I think it's the best way to build an API) -- but it's very suboptimal from a users point of view. Realistically it's hard to get users to do the provably fair verification once, let alone for every single bet. Also with the nonce system even if a user doesn't record their server-seed hash (which, let's face it: almost all the time) once a person has made more than half a dozen or so bets (with the same seed) it doesn't matter as it wouldn't be possible for a malicious site operator to find collisions anyway.

I think the only way to make the one-seed-per-bet system really useful for users would be to provide a (small and easily auditable) browser plugin. The browser plugin itself should randomize the client seed (when a bet is happening) and itself verify the result of the bet (issuing an alert when it doesn't verify). The browser plugin should never advertise itself, so the site has no way of knowing if the user is using it or not.

That said, I do think it's just far better to use a nonced-based system.

By adding a nonce you will be able to allow your users to easily verify bets. Otherwise they are forced to verify bets one by one. This isn't exactly a good way to go. You could possibly change the server seed hash knowing what the next client seed is thus outcome. I don't see this as a proper method of fairness.

When you say if your server was compromised, the hacker would only know 1 outcome of the roll, wouldn't they be able to consistently see the next server seed hashes (Unhashed) and thus do exactly the same thing?

I don't personally see this as a optimal way of going about true fairness.

Both described methods have negative consequences.  Utilizing an incremental nonce with an unchanging server and client seed prevents real-time verification of rolls, which is obviously useful to people placing a lot of automated bets.  This is, in my opinion, a major flaw.

The author of this thread states that the intent is to protect the average gambler.  The average gambler is not going to notice if a site selectively overwrites its client seed generation code.  The average gambler is not going to understand that a 14 digit numeric client seed, like what I just received from Primedice, makes precomputation attacks much easier.  Additionally, I highly doubt the average gambler cares or could even understand anything being discussed in this thread.

I don't mean to give the impression that this is a bad or misguided idea.  Honestly, as Primedice is a major part of this, I probably shouldn't comment on it at all.  Regardless, it's wrong to make people think that adding a nonce is some kind of magic solution to fairness.  I think this initiative would make more of an impact if they were to champion the idea of strong, user-generated seeds.  I also think that if this group is going to be calling out gambling sites, then perhaps it should call out sites that generate weak client seeds.  Perhaps sites should generate a client seed equal in complexity to the server seed.  For instance, Primedice generates a 256-bit server seed, I'd say they should strive to also generate a 256-bit client seed, rather than the ~40-bit client seed I've received.

You make some really good points. The nonce system isn't perfect, and has some major shortcomings such as requiring a seed change to verify as noted. That being said it is still significantly stronger than the quite popular new server seed and client seed pair per bet system.

Thank you for pointing out this shortcoming by PD. This is the whole point of all of this, to encourage an informed discussion that pushes all of us forward. Indeed this is something I will raise with our developers. Perhaps this is also an argument that there should be a 'standard' for provably fair cause otherwise one website can use ultra strong fairness and other sham fairness and still claim to be 'provably fair'. Maybe it's time to create a new term for a strong standard.

Our goal needs to be to simplify provably fair to protect the average gambler. When a normal player goes to the casino he's able to visually see that he can influence the result by 'cutting the deck'. Instead of just trying to teach average players this complicated algorithm we should try and find solutions that are equally fair yet simple. I've just put up a bounty here: https://forum.cryptogambling.org/topic/18-1-btc-bounty-improve-provably-fair/ 1 bitcoin reward for a fresh system which solves the complicated nature of provably fair, 0.1btc per user for small edits that simplify the system.

Fair point, although 256-bit client seeds is way overkill. Not only would a malicious server have to guess which way you're going to bet (hi or lo), it would have to do a comprehensive search of client seeds for each server-seed it wants to test and then see if there's any statistical deviation. This is already out of the realm of possibility for an 80 bit seed, let alone bigger.

Furthermore, the statistically deviation drops off rapidly with a large amount of client seeds. Even with 40 bit client seeds, I can't imagine it's possible for a malicious operator to brute force a server seed that even has a 0.1% uplift over a randomly selected server seed.

Plus the reality is that for real provably fair validation, you don't want to trust the client anyway so the client seed complexity is pretty meaningless anyway.

I agree with you about the forum not being that active, I would have assumed that there would be a little bit more suggestions of gambling sites to verify in the future.
And I don't think that they are affiliated with anyone, at least the website doesn't show it and it doesn't look like they're promoting one operator over another.

I mean, they're not using affiliate links and their articles are very objectively written, they're basically offering you some technical explanations.

Now I do think that they should keep adding more casino's to their list of verified operators, a few weeks without activity isn't that great if you only have 5 verified operators listed.

I don't really think any of the large actors are doing anything malicious.  Smaller operations might try to implement something like what is discussed here: https://bitcointalk.org/index.php?topic=1494470.0.  Utilizing a nonce would not preclude that type of attack.  That said, complex client seeds wouldn't either.

In any case, my argument for client seed complexity is to prevent a class of attack that I haven't seen discussed much but certainly exists.  I'll again reference Primedice, not to suggest they're doing anything malicious, but it's an easy example.  They generate a client seed as such:


This happens whenever the Change Seed modal is opened (or closed, this is probably a bug.)  One problem is that in major browser implementations, Math.random() is implemented using xorshift128+ and is predictable.  Another is that the value of the date object is easily guessable.  Again, I'm not stating that Primedice is doing anything wrong, but when the client seed generation code is called, a call to Facebook's Pixel Events service is also made that easily identifies the fact that the user has opened that modal.  If Primedice were to collect the results of just a few calls to Math.random(), and they don't even need to be consecutive, then it would be trivial for them to predict the generated client seed.

Generating a 256-bit hex string would not fix this, the same attack could be used.  Using a csrng would fix this, until the site decides to overwrite that code in a targeted attack against a high-roller.  The player producing their own complex seed will fix this problem.


I really don't mean to place such a focus on Primedice, but in addition to the above, I also noticed that the client seed never changes when the user attempts to randomize.  Upon opening the relevant modal, the component components.ModalsWrap.Modals.Seed.Seed.newClientSeed has its defaultValue attribute set to the new random value.  However, it doesn't look like the component's state is ever updated, so the component is never rerendered.  When the Change Seed button is clicked, the currently rendered value in this component is used, rather than the new random value.  In effect, this causes the user to always have the same seed unless they enter their own.

Yes I agree that a 256 bit client seed is over kill however with the fast CPUs of today it doesn't really consume many resources.

Most of the larger sites are already hosted on Xeon dedicated servers and most of the time those CPUs are pretty much sitting idle. The hashes are done very fast on those CPUs.

It's not really about performance, but about the user experience of it. Big hashes are pretty scary, while for instance in bustadice.com, my client seed is: "pleasant macho match" which was generated using strong client-side cryptographic random number generation. Granted there's not that much entropy in it, but it's something that is very easy for me as a human to remember (and thus be sure it didn't change).

And I don't really think low-entropy is a big deal, the amount of uplift a malicious picked server-seed is pretty much negligible -- and rapidly approaches 0 when a user keeps betting.

Plus like I said earlier, players in general don't really have the ability to audit the game client each time -- so really should be picking their own client seed.

Easy to remember client seeds should be implemented more. Not sure why we haven't taken a similar approach. A lot more logical than a string.

When will this be happening? Waiting to see how this pans out, really interests me the whole initiative behind this foundation. It's something Bitcoin gambling needs but it needs to happen soon.

I've noticed a lot of websites recently who are using the guise of provably fairness to legitimize themselves but in fact since educating myself about how it all actually works, fall into one of the subpar categories Rhaver was mentioning. This should definitely be brought to light as me a few weeks ago would have never noticed anything

It's amazing that a single factor can change a whole lot of things. Though, since I am not an expert at how things work on the casino's side of things, is provably fair truly that formula? Is it really [server seed] + [client seed] + [nonce]? Is there no other way of creating another form of provably fair environment? Another thought is, how secure is it really if the formula is that? Is there no way a casino can cheat if that formula is used? Pretty interesting.

I like

This is a really good initiative to help players to have more confidence in the crypto-currencies gambling scene, as there are more and more new dice sites coming out into the gambling market quite often, some of the dices sites claims to be 100% provably fair but in fact the system is not totally perfect to be fair to the players.