Topic: [EDU] Provably fair and how it can be exploited by casino owners against you. (Read 8620 times)

The first page of this topic Kingsportzruls makes a precisely pin point with deadly accuracy comment regarding increased betting. He is correct to say that while a casino plays fairly with very small amounts of cryptocurrency but larger abets don't result in the same odds. I've found this to be true in most all these Bitcoin dice casinos. www.999dice.com, www.trustdice.com, and some others I haven't played in so long I've forgotten the names of. Now I can easily see the odds shift against the player when bets are increased in some of these casinos. And not just because I have lost because I do realize that even if the odds are .01 percent house edge eventually that small percentile will beat you every time in the long run. So this isn't a sore loser talking cause I'm perfectly aware of the fact that the odds will beat you in the end. This is someone who doesn't like a shiesty cheat. I mean those casinos get highly pissed if they suspect someone of cheating them but we're sore losers or get banned or whatever other sanctions they impose at their discretion, confiscating players winnings , deposits and such. With the odds in the hoses favor they can't lose in the end so there's no excuse for cheating folks. Kingsportzruls is obviously intelligent , highly experienced, honest and respectable to shed this light on the subject and in words I could have never said better myself. Thankful for his time and wisdom on the subject at the very least. And hopefully you watch these 2 casinos I have listed for yourself if you decide to play there. I will update if it comes to mind some others that come to mind. I enjoyed this discussion even if it is an old thread.

Hi Trevar

Recently while trying to gain knowledge on probably fair I came across your post over bitcointalk. Where I found a reddit link to your post but unfortunately I think that post has been removed from network.

Can you please share some knowledge with me on probably fair system and how I can save myself from being a victim by these bitcoin casino sites.

I have already lost a lot by their manipulation's.

I'm eagerly waiting to hear from you. Please help me.

Regards
Haris Harrison

Looking at the old old pages of the gambling section makes me have a lot of memories. Some unwanted, some nice to think about. One of the pages I came across this. Please do keep this in mind when you are playing at these "provably fair" casinos and always change your client seeds when playing, I cannot stress what this thread represents enough so I'm bumping it both for old memory's sake and also to help some of you new players as well.

From all who have been around BTC since my introduction to it in early 2013, some of the memories I shared with many of you I greatly remember. Going back in time, wow to how much has changed both in bitcoin, this forum and in my personal life.

Anyways, enough careless personal thoughts, go have fun and good luck with your endeavors whether they be gambles or investments!  

That is true.

Provably fair has become an essential in the Bitcoin gambling industry. I don't think an honest Bitcoin casino should have anything to hide.

Oldminer, Are you from India? Reason I ask I would be more then welcome to use Google Translator to help explain more in detail on why provable gaming is an important aspect in the new digital gambling atmosphere. In a nut shell these none provable casinos use old dinosaur software that has been proven time and time again to be unfair to casino players. What's ironic is the house always wins in the long run so there is no need to steal from clients as generally they will lose at some time. This is one of the reasons why Douglas is so successful. People know they are getting a fair handshake and even if they lose they usually can accept the fact it was a legitimate roll on the dice. (I still bitch and moan to him on occasion though when I lose) 

Any gambling company that still promotes unprovable gaming clearly knows they are a dying bread and as the gambling community continues to educate themselves regarding provable gaming and the concept behind it. A majority will jump ship even if the quality of designed games lags from the antique none provable kind. Within a year I would bet a majority of remaining online casinos especially in the bitcoin field will all offer provable gaming. If not they will go hungry because guest no longer will be willing to "lose" coins knowing ahead of time the odds of winning is slimmer than what it would be in a provable gaming casino.

Do you feel up to talking about this now, or are you just going to make zero-content posts like the above?

Maybe we could take it to your self-moderated thread so you can delete anything I say that makes your scam casino look bad.

LOL. Won't the admins remove OBVIOUS scams ? Go away bitwincasino!

Oldtimer/Bitwincasino =scam

lol sure they dont dooglus..sure they dont..haha 

That's a good idea.  Read the article, see if any of the points it makes could realistically happen on the site you're thinking of playing, and if so talk to the site operator about how he can prove that he's not cheating in such a way.

A lot of the points the article makes just don't apply to most new provably fair sites.  There's still a responsibility on the player to check the results for himself and not blindly trust the site to be fair because it says it is, but provably fairness really does mean you can check whether you are being cheated or not.

Hahaha same, the first time I read it I was like "why the hell would the say their site is probably fair??!"... anyway, very interesting read. Will definitely make me think twice about putting any wagers on any of these sites.

The one and only Provably Fair Verification Form you will ever need.

It seems there is an implication that I have a "liking" to anyone or anything. If you must know, I don't particularly like any site. But like you just said, there is no fault in anything I have said, regardless of perspective.

You can make accusations without proof, but that doesn't look right to me. I don't send innocent men to jail.


Probability is not certainty. You can certainly say for example, that if any single bitcoin casino now gets 500,000 BTC in total deposits, the operators will probably disappear.

I can assure you, from gut feel, without proof, that if this all happened to the top 4 dice sites, including PD, CR, JD and SD, none of them will disappear. (SD can't accept deposits yet, so we will just see record gambles in the blockchain.)


I don't have the data, it was never made publicly available all in one place. We'll have to request for it. I feel though, that no matter how accurate and legitimate this data will be, you will consider the source suspect.

I can't help you there then.

Your belief, without proof, is the same as my so called Gambler's Fallacy, which many people consider the same as Santa Claus and the Tooth Fairy.

Also, another problem with that is you will be selectively using a limited set of data. Remember, the systems as implemented DO NOT CARE or DO NOT KNOW how much you bet. The bet amount is IRRELEVANT. If you take away 99.5% of the data, you are only using 0.5% as your sample, and the variance there will only be 0.5% of the whole.

You have to use everything. Scrap out the bet amounts. Analyze that. If those are all within standard statistical deviations and norms, I hope that provides enough proof.

I do agree, I am a good guy (self-serving), and I am in communication with the operators and owners of those top 4 dice sites.

If you have any particular suggestion, you can post here or PM me, I will forward it to them, and hopefully they will improve their current implementations. There are some obvious ones need right now, I can see that. While it's not yet happening, do yourself a favor and change the client seeds yourself at every roll. You can't get any more fair than just doing that one thing. Regardless of how much you bet.

I don't see TrevorXavier posting any drafts of his Provably Fair 2 system yet. And I honestly can't see how anything can get fairer, than for example, my own weekly lotto drawing. Although this is a really slow way to try to implement on a dice site.

One last thing, in poker sites, they use simulations of their RNG to show you that 1 million hands are not being manipulated. The site does not know who the players are, does not know how much is the pot, and does not know who will fold or who will win. And there is nothing provably fair about what they do. Think about that.

Here's a suggestion: Would people be willing to put up a fund where I can collect large amounts of BTC, then I will gamble it and gather statistics? The sites will not know it is me since I will be using an anonymous account. As the lead investigator, I will place the high stakes to investigate any possible cheating. Any assumptions the site makes based on bet discrimination to attempt to cheat our coins away from us will result in detection of any such exploits.

I've tried the "Group Bet" thing before, and didn't get much (I gathered about 20 BTC total.) Plus some people are violently opposed to me doing this (not the site operators.)

How is it that someone can take a liking to someone they have never met and only after a few brief exchanges. Dabs you are a good guy. You seem to be coming from an academic/statistical perspective, and there is no fault with anything you have said based on that perspective.

You are not focusing on the correct particulars however. Take your 10 million bets from PD, JD and co and remove 99.5% of the bets. Remove all the micro bets and lets talk about bets only at 0.5 btc and above.

My point of contention is - quote "Quote 1 “Bet Discrimination Under the assumption that an investigator will not place high stakes to investigate cheating, the house can safely offer a fair game to those using play money or very low stakes. As the bet size increases, so does the probability of an exploit."

If you are able to do so, please run your analysis on the data of PRIMEDICE for bets 0.5 btc and above and report what the house edge is currently for those, and only those, bets. (For the record, i believe Just-Dice to be far superior and fair from my experience.)

Quote from TrevorXavier post : "If a house cheated, they would eventually get caught. Not necessarily. The house only needs to bring their theoretical house edge to 1-2% to see significant gains. Additionally, if the house concentrates its cheating on a minority of players that it can safely assume is not investigating exploits, the cheating can continue without detection."

Dabs, if you do manage to calculate the house edge % for PD for >0.5btc bets, I'd be most interested in your explaining same should that % come back at 2% or better.




 

So, so far, you are saying, these sites just don't feel right? But you have no other proof or validation other than gut feel?

The problem with this "minute" sites, is that suddenly you don't take 6 months to 1 year to achieve the milestone 5 million bets. You take 1 week and you have 10 million bets.

What took SD a year to achieve in terms of numbers (not bitcoin, but number of individual bets) only took a month for all 3 other non-blockchain based dice sites (CR, PD, JD).

So we see their variance and results come out faster than what seems normal. If the site in question seems very lucky, then an exploitative player could reverse the rolls and make the site very unlucky. Any variation from statistical norms would be a pattern seen by all these analysts and ... the site will go broke very quickly.

While the results look very improbable, they are not impossible. We know the math. It happens. Case in point, it did not take a million rolls for the 1 in a million bet on JD to win. Two separate people achieved it using javascript bots running the entire night and day, thus skewing the site luck for awhile during it's first "minute" of existence.

In JD's example, if the players do not change or randomize their seeds, the sequence has been laid out well into the future (the owner can compute the next billion rolls and know the results.)

Dabs, thank you firstly for contributing to this discussion in a professional manner, and providing constructive and meaningful input. I can respect a person when they present in such a manner. Given the topic, it's all too easy to bring these discussions down to toilet level, with name calling, throwing terms like 'sour grapes', 'sore loser' etc etc around. So i respect what you say.

I have over 2 decades of gambling experience, and i have studied quantitative analysis at college. Further, placing a $1,000 bet these days unfortunately does not mean the same to me as it once did. But whatever, you lose some, you win some. Know what you are getting involved in, and take the outcomes like a man.

BUT, if you have vast experience in anything, you know when something is not right. This is what i am saying, from my personal experience, past and present, i believe a particular site is not 'right'.

I agree with what you said above. But also remember that coin has too sides. All of those loses you mention are statistically possible, but the same goes for such a run on wins. It is possible to win 6 times in a row on 12%. But on all these threads, all the bitcoin sites etc, and with all the chat and people watching the play going on, i personally haven't yet heard of any stories of such 'magic' run of wins.

Why are so many people coming out saying 'man, a lot of bad streaks on such a such site', or 'i know it is possible to go on a bad run, but 10 loses in a row, 3 times, this quickly, wtf' etc etc.

Some sites have only been running a 'minute' statistically speaking. And already have claimed victim after victim with 'statistically acceptable variance' blah blah blah. Such runs (good or bad) are possible, but very RARE, like 1 time per 100,000+. For such runs, and coincidentally all to be bad runs for the players, to happen within the first 'minute', well come on, are those site owners REALLY THAT LUCKY? and us players that unlucky?

I'm a realist, and I personally believe something is not right with some sites.
 

While the second option is not exactly something good, it might just be an innocent mistake by the operator. So, please, clarify if your preference is for the second option with the additional constraint that the operator should never make mistakes on that.

If your preference is for something else, then I still don't know what you prefer, neither what is your actual point (and this should be very clear if you are interested in continuing with this). I've read your original post and got the points you made, but now I can't see what exactly you are after.

Thank you for the question!

Nothing from my original article should have led you to that conclusion, and neither one of those preferences is appealing. The research conducted should help players understand what "provably fair" is and what it isn't. It can be a good-faith effort on behalf of a casino to alleviate concerns of cheating, but it isn't a means of absolving a casino of all liability. I do consider many of the web-based implementations of "provably fair" to be quite weak, since they claim to create an environment that makes it "impossible to cheat" players or instill "ultimate trust".

If my research helps advance the frontier of "provably fair", then I'll consider it a meaningful contribution to bitcoin. Thanks again.

I assume I'm a bit confused here. Can you clarify which of the following you prefer:

• Make a casino, never mention it is provably fair, neither provide description about how it operates
• Make a casino, mention it is provably fair and provide a description about how it operates, eventually get caught because people found that it was not doing what it promised

? So far it seems you prefer the first method, and the casino might very well operate in a fair manner. The thing is, if it doesn't operate in a fair way, then people might never find out. The second way is much clearer to everyone, and people interested on it will certainly check what it says.

Certainly, and yet SkillsOnNet, Spielo G2, Scotland, Winaday, and GameTech (formerly FutureBet) have been caught and are still in business. The goal of my analysis was not to destroy "provably fair", but rather to point out its potential weaknesses in the hopes that it does become stronger. Without careful study, any newly-minted, nefarious casino can tout their "provably fair" system and get players to participate in an unfair environment.

You know what happened to Absolute Poker and Ultimate Bet? They got caught cheating. They are now gone. (Well, the government is now auctioning them off.) Those aren't even bitcoin casinos and don't have any provably fair system at all. They were however audited by some government entity and certified. But nothing that you, as a player, can do to verify the game you just played.

Unfortunately, this is a misleading statement. And I say it with the utmost respect, as I have enjoyed – and will continue to enjoy – discussions with casino operators.

First, the statement offers nothing towards the cryptanalysis of "provably fair" – meaning, a casino operator could remove all references to provably fair on their site and simply say, "We do not cheat. If we did, we would get caught and lose all of our customers." This is a simple promise. It offers little towards any cryptographic reassurance that bets were handled with integrity.

Secondly, it is difficult to follow your logic that one discovery of cheating would lead to catastrophic loss of the entire customer base. For one, if the casino was engaging in bet discrimination, only a subset of players would be subject to exploitation. And throwing an accusation would be difficult to reproduce, given that a) other users may be unable or unwilling to bet at the same high level as the accuser, and b) the exploit may be infrequent, and c) other users betting below the discrimination level could accurately say, "I was never cheated. I verified all of my bets."

The burden of proving fairness (provably or otherwise) must remain with casino operators, not the players that enjoy playing them.

This statement here I am calling bullshit on.

For 0 confirmation blockchain games that clearly state when they change the secret and display it there is only one possible way to cheat without getting caught.

A 0 confirmation casino could argue that their bitcoind node had not seen the bet before the secret changed. This allows for a ~10 minute window of abuse, that being said all players need to do is stop betting 10 minutes before the daily secret change and wait for the new hash to be announced.

Checkout satoshiroulette.com for an example (disclaimer Ive helped with their code and they have previously paid me to advertise on arby.pl), they log announce each days secret in the bet log so you can see exactly which bets were placed before and after the change and verify there were no obviously delayed (1 conf of greater) bets.

In this case Provably Fair is the absolute best random odds gambling you can hope for.

Hi, I'm not defending or defaming any particular site, regardless of what they begin or end with, but @kingsportzrulz your statistics, even for the so called large bets are within variance.

The site you mention in particular has all the elements of being provably fair.

The article you mention makes no direct attack on any casino, just a lot of hypothesis that goes against every major bitcoin casino, and against their self-interest. Bitzino in particular, since it was the one specifically mentioned, can't afford to do any of the proposed cheats. Their volume of BTC and players is too low to risk it.

If you find a statistical anomaly, you had better best exploit it (even though that's not fair, for them.)

In fact, if there is one site where it can even be attempted, that would be on the seemingly fairest and justest of the dice sites. With 50,000 BTC invested and a current max profit over 500 BTC.

The site clearly states its terms of being provably fair, with sample code, and with third party scripts. What the article mentions are changing the codes on the fly, using bet discrimination and using html partials and javascript alterations.

The ones that can do cheat, are the ones that aren't even provably fair at all, such as the majority of internet online poker sites. I'll specifically mention the top 3, PokerStars, Full Tilt Poker and Party Poker. Between the 3 of them, they have maybe half a million players. That's 500,000 people online, all playing poker, all betting from $1 to $500 per call or raise, depending on the stakes.

If there are sites that can get away with it, those certainly can. First, their games are not provably fair. Just certified by some offshore government or gambling commission. It's almost as if they are saying "Look, we'll record the game on video to prove it is fair." And of course, we all know what's wrong with that statement.

Out of the 500,000 people playing, they only need to cheat 1% or even less. Maybe just 1000 people. Disconnect them all, consider them all-in, then grab the pot.

So I dunno. That article, while being a wake up call, stirs a lot of debate. You, as the player, of all sites you visit, have to be responsible enough to at least verify and understand the probabilities and the consequences of gambling. You have to understand that you can easily lose 50% 20 times in a row. You have to understand that you can lose 111 times in a row on 10%. You have to understand that you can lose 8 times in a row on 90%.

Because I've personally seen it all happen. And I personally verified each and every bet as fair. And it does not matter what the amount of the bet is, because the systems all of these bitcoin dice sites implement does not account for the size of the bet.

See, if the site offers the following:

1. A server seed or secret that you are either shown, or have the hash for, shown first.
2. A client or player seed which you can change after the first step above.
3. The formula to actually compute the result of the roll after the fact.
4. With or without a nonce or salt or some other random or incrementing value.

I don't see how any one can righteously claim that it was ever unfair.

All other traditional casinos and live dealers and all current poker sites (including bitcoin based ones) are not provably fair at all.

It's a good thing that SD and Bitzino and all the blockchain based games, and all the ones that attempt some sort of Provably Fair system even have those to begin with.

It is your responsibility to take advantage of the fairness offered. If that is difficult because of the particular site, that's only a logistical or convenience problem. You can take it against the site, but you can't accuse them of being unfair when they give you the chance and the tools to make it so.

Which is why, I am afraid, if I come up with my own casino, such as the popular card games, BlackJack, and even Poker, that no matter how many hashes and nonces and secrets I use and reveal, someone somewhere somehow will still accuse me of being unfair.

Online play has allowed people to bet a million times more than in any brick and mortar casino, that's why we see all these "weird" numbers pop up. Just bet a billion times on 98% chance to win and you will almost surely see 5 or 6 losses in a row. It can happen within the first 100 rolls.

While I'm at it, I just lost 6 times in a row on 87.7779% about 4 or 5 weeks ago. I'm going to bet a bunch my next roll, which is still waiting, is going to win. (I have another thread for that.) If I win, I will withdraw my prize. If I lose, then I don't. Both are fair. (This is gambler's fallacy now speaking; hehehe.)

Firstly and MOST IMPORTANTLY - I have no affiliation with KingOfSports (KOS) whatsoever.

So KOS if this comes back on you in anyway, I sincerely apologize.

But I agree and share some of the same BELIEFS as you do. But what I BELIEVE is what I believe. Just because a belief or two are shared does not mean ALL beliefs are shared.

My personal BELIEF is that there are sites claiming to be provably fair, however are NOT FAIR at all. My current site of ‘dishonor’ I will not name specifically, but I will say it starts with ‘PRIME’ and ends in ‘DICE’.

I will again refer to the excellent article written by TrevorXavier: http://www.reddit.com/r/Bitcoin/comments/1frm4x/provably_fair_by_bitzino_not_provable_with/

And provide a couple of quotes from it I also believe to be true.

Quote 1 “Bet Discrimination Under the assumption that an investigator will not place high stakes to investigate cheating, the house can safely offer a fair game to those using play money or very low stakes. As the bet size increases, so does the probability of an exploit. A house can also analyze betting patterns (progressives) for ways to minimize its short term risk of ruin.”

Yes, a lot of players (myself included) on some sites have many hands/spins/rolls of wins, thousands of wins. So many wins (correct statistically and all or even above odds to player even), however at such micro bets. BUT, I am sure some of you (myself included) bet a reasonable amount each go at times as well, say 0.1 low end, 1.0+ btc per go.

What have you / I personally seen at 1.0 btc per bet. WOW, instant such a bad run, just an unlucky day, its gambling, you will always lose, don’t gamble. 9 and 10 losing streaks in a row at 50%, several times over, and within 200 bets. 7-8/10 loses at 70% time after time. Wow, kind of thought at 70%, I should have been winning 7/10, statistically I mean. But yeah, loses like this can happen.

Go back to micro, and it’s within statistical limits again, even win, win, win, win, Yay I just won 0.000055 btc.

Quote 2 “Third, it can employ these cheats to minimize risk during progressive betting. Any player using Martingale or other betting system will always lose in the long-run, but short-run gains can occur. As such, producing guaranteed losses for the player over big bets will factor into the house's profit-maximizing strategy.

Fourth, a house can offer more smaller wins to players by cheating large bets, increasing word-of-mouth advertising. For example, suppose a draw poker game accepts bets from a micro-bitcoin to 50 BTC. If the house forces a player loss at 40 BTC…”

Quote 3. From the discussion in that article “A main point of the article suggests that a house could effectively cheat a portion of its players by segregating them through bet or browser discrimination. By implication this means a majority of the cheats are performed on a minority of players.”

So the people you see complaining about sites cheating are these ‘minority’. And the people you see defending, are those ‘majority’.

If you are in the ‘majority’, sorry you don’t have enough cash to bet more than a dime a go.

If you are in the ‘minority’, then chances are some sites are cheating you.

Got to love when sites are smart enough to give countless free micro coins out and then let players play fairly with them. ONLY TO CHEAT PLAYERS WHEN THEY DEPOSIT OWN FUNDS AND BET LARGER.

Yes, any outcome is statistically possible. No one is forcing anyone to bet. But claiming to be a fair site, when you are not, just because there is no regulation, is straight up scamming.

If it walks like a duck, quacks like a duck, and looks like a duck, time and time again, based on observations by independent person after independent person, well….

Well, just read the linked article folks. Then re-read it. And to anyone who comes out defending certain sites, stop being ass-kissers please, man up and place several dozen above 1.0 btc per go bets, and THEN see how fair it is, statistically or otherwise.

I'm afraid that is not how it works. To me, that is like saying a formula resulting from a theorem is only valid if you, as the user of it, prove the theorem yourself.

Nevertheless, I agree that users should investigate the provably fair method employed and verify/question it.

That's right. It's not fair until you as the user proves that it is.

That says it all!

Provably Fair is just a word without proper "auditing".

Try to (really) perform the proper calculations in order to prove it (by yourself) it's fair!

Even Provably Fair Systems may be manipulated as everything created by humans.

"Provably Fair" without proper auditing and testing is just an "lonely" word by itself...

I just thought I'd chime in about provably fair at Bitcoin Video Casino.

It's absolutely crucial to our business that we never get caught cheating the user. If just one user discovers that we are cheating, all trust is gone, and we will lose all of our customers. Therefore, it is in our best interest to run a legitimate and fair casino. From a financial perspective, it simply does not make sense for us to cheat the user.

We have a green "verify" button that users can click to check every game played. The verification code is run entirely client-side, so the user can be sure that the game played was fair.

The source for all client-side code, including the verification functions, is always available at https://bitcoinvideocasino.com/static/

Your last paragraph is true insofar as there is no way to cheat SHA-256 or SHA-512. I mean, there really is no way to cheat a cryptographically secure hash function that spits out 256 to 512 bits with several rounds of processing save for brute force collision attacks.

As reference, 128 bit symmetric encryption algorithms such as AES will remain "uncheatable" for the foreseeable future. You know what they say about it right? These numbers have nothing to do with the technology of the devices; they are the maximums that thermodynamics will allow. And they strongly imply that brute-force attacks against 256-bit keys will be infeasible until computers are built from something other than matter and occupy something other than space.

For both web-based and downloaded clients, I think the issue would be a proper accounting of every step of the way. And the player himself can actually verify that his client seed is what he actually chose. It's as simple as adding an extra character or replacing one from his client generated random seed.

If the client and/or the website provides complete logs for everyone to download and see, it gets us closer to being more provably fair than other implementations.

It also depends on the implementation of the system for the game. If the casino makes it very easy to verify the results, and makes it very easy to see that there are no so called "html partials" or modified javascript, or whatever techniques you talked about in the original article, that should count for something.

The difference between the web-based and the blockchain based games are the public records. Even if you operate a web-based game, or even a downloaded client game, if you, as the casino operator, take steps to record and account every possible angle or move, that should count towards securing your provable fairness.

Personally, I'm thinking of how else can my card game get rigged, when everything is as open and transparent as possible while adhering to the rules of the game (where some cards remain secret to the grave.)

I have a separate thread for that, btw. PM me if you can't find it. I don't want to turn this thread off-topic.

Thank you for the questions, Dabs and jeffreylin_. I'll try my best to answer the questions without getting too detailed.

For now, I will also assume that anyone reading the following has read my first analysis.

In a nutshell, manually changing client seeds and recording server hashes does not necessarily make a gambling site fair. While an individual can take additional steps to decrease the likelihood of being a victim – such as manually changing the client seed – doing so does not increase the provable fairness for other players. Since cheating need not be uniform, an malicious casino may continue to operate in an unfair manner for a subset of all players (as illustrated in my post on reddit). This essentially "breaks" the concept of "provably fair," which – to my understanding – is advertised as a system to prevent a house from cheating.

In regards to downloaded clients, I believe you may have answered your own question. For the most part, I would not expect a downloaded client to offer anything better than a web-based interface. There has been talk of offering a browser extension or similar tool to scramble client seeds and monitor results atop a web-based client, but I haven't seen one in the wild yet.

With respect to SatoshiDice, my colleagues and I focused primarily on web-based implementations of "provably fair" since the number of web-based gambling establishments seem to outweigh the number of blockchain ones. To say that "there's no way to cheat it" (with all respect) is too strong of an assertion: cryptographic systems are only expected to weaken over time.

Hope that's quick enough to avoid a tl;dr. Please let me know if you'd like some clarification on anything.

So basically, you change the client seed and make sure you see the server hash before you believe that a gambling site is truly fair?

Hi Trevor,

Your analysis is only applicable to non-blockchain based games, and such websites that use HTML5. It doesn't apply to SatoshiDice at all, because, well, there's no way to cheat it, it's all in the blockchain.

Does this also not apply necessarily to other games that use a client? For example, card games that require software to be downloaded. You can certainly sniff the network traffic to detect anything, but software could be "rigged".

Actually, for most card games that do not reveal the entire deck, such as poker, I haven't seen any method of "Provably Fair" being implemented at all.

Hi, everyone! Thank you for highlighting my post. It received a warm response there, and I spent many weeks thereafter fielding questions and looking at comparative implementations.

I'll be releasing another analysis of "provably fair" in the coming weeks. While I do love reddit for its ease in following discussion threads, I'd be happy to release it here on the appropriate forum if it would make more sense. In the meantime, if you have any questions about the post, please feel free to reply or contact me privately. I will do my best to answer in a timely manner.

Note: You can verify that I am the original author by revisiting the post on reddit (http://www.reddit.com/r/Bitcoin/comments/1frm4x/provably_fair_by_bitzino_not_provable_with/).

Congrats! Now you know we're fair 

I just won a BTC off you... red never fails.

Pleasure doing business.  

The entire concept of provably fair was originally intended to give an added value to Bitcoin casinos over other online casinos.

It would be a shame to find out that anyone is taking advantage of the players by fooling them to think they are provably fair while they are not.

Our provably fair Roulette has one public spin every minute rather than a spin per player hence we can't change the result, or show different results to different players. We publish the results the next day so the players can verify that the results they saw were the actual results that were supposed to be shown.

This is arguing semantics, but all Provably Fair games are actually implementing Probably Fair math. However, this probability is very very very extremely astronomically low of being anything but fair. We are using anywhere from 256 bits to 512 bits, which means 2^256 to 2^512 chance of hitting collisions in the hash functions used. More or less.

My brain always reads this as "Probably Fair". Could be it was trying to tell me something!

If that's the case with bitzino, I've lost quite a few BTC's there  .

Yup, really hope newbs see this and understand all of it. I truly do wonder how many BTC sites are rigged this way.

I agree with this observation too. Also, just because a site says they are "provably fair" doesn't mean they won't take your coins and run.

Yes. I agree.

Also make sure you see the hash of the server before you are given the chance to enter your own client seed.

I think this is part of the idea behind mem's Provable Results vs Provably Fair.

Someone posted this article in one of the threads here. Had to highlight it as many sites are being questioned regarding this.

MUST READ ARTICLE:

http://www.reddit.com/r/Bitcoin/comments/1frm4x/provably_fair_by_bitzino_not_provable_with/

Number one rule: DON'T assume the casino you're playing at is honest and that their provably fair system is fair.

ALWAYS and I mean ALWAYS change your client seed to something different. This is one of the ways you protect yourself. It takes a second to do I know which is inconvenient but truly do it.

*Note: I make no personal accusations against any site in this thread. This is an educational thread focused on providing users the understanding that just cause it says provably fair and it verifies, it does not mean it truly is a fair system.*