Cheaters (double spenders) and what the gambling sites are doing against them

[BitcoinBlackjack]

It recently came to our attention that many people (including people on this forum) are attempting to cheat on gambling websites (especially those that have a 0 confirmation deposit policy)

Here is how it works:
- Cheater finds a gambling website that lets you deposit with 0 confirmations
- Cheater sends BTC with a low fee, which takes anywhere between a few minutes to over 1 hour for it to receive the first confirmation
- Cheater plays on the website:
   ~ IF he is winning before the first confirmation hits, he "allows" for the transaction to go through (by not double spending) and then withdraws the winnings once the transaction is confirmed.
   ~ IF he is losing before there is the first confirmation hits, he double spends the transaction with a higher fee to another wallet of his.

This effectively gives the cheater a window of a few minutes to play and decide if he wishes to allow the transaction to go through or not.

When we had our 0 confirmation policy, this happened to us (www.BitcoinBlackjack.com) many times.
And now that we implemented a 1 confirmation policy it seems that the cheaters have taken their scam elsewhere.

We have personally spoken to many other gambling site owners on this forum, and many of them have also switched from a 0 confirmation to a 1 confirmation deposit policy in order to protect themselves.

Unfortunately, this does not benefit the experience for the players (since they have to wait for their deposits to confirm each time before playing). But it seems to be the only way to combat double spenders.

What do you guys think? Players? Website owners? We would love to hear from your experiences and see if there is a better solution.

[joksim299]

Have you tried to male only deposits with sufficient fee available for playing instantly?(check Bitsler)
I play BJ at Coin Royale and they allow 0 conf. deposits for my account.

[aakashsangwan]

It recently came to our attention that many people (including people on this forum) are attempting to cheat on gambling websites (especially those that have a 0 confirmation deposit policy)

Here is how it works:
- Cheater finds a gambling website that lets you deposit with 0 confirmations
- Cheater sends BTC with a low fee, which takes anywhere between a few minutes to over 1 hour for it to receive the first confirmation
- Cheater plays on the website:
   ~ IF he is winning before the first confirmation hits, he "allows" for the transaction to go through (by not double spending) and then withdraws the winnings once the transaction is confirmed.
   ~ IF he is losing before there is the first confirmation hits, he double spends the transaction with a higher fee to another wallet of his.

This effectively gives the cheater a window of a few minutes to play and decide if he wishes to allow the transaction to go through or not.

When we had our 0 confirmation policy, this happened to us (www.BitcoinBlackjack.com) many times.
And now that we implemented a 1 confirmation policy it seems that the cheaters have taken their scam elsewhere.

We have personally spoken to many other gambling site owners on this forum, and many of them have also switched from a 0 confirmation to a 1 confirmation deposit policy in order to protect themselves.

Unfortunately, this does not benefit the experience for the players (since they have to wait for their deposits to confirm each time before playing). But it seems to be the only way to combat double spenders.

What do you guys think? Players? Website owners? We would love to hear from your experiences and see if there is a better solution.

I see that this is the best option other than that , because like what you told this scammer will find lot more options for this cheating.

[DarkStar_]

You could do what luckyb.it does and wait for it to confirm with a low fee, or have instant play with a fee of at least 0.0002BTC. Should stop most double spenders, as it needs to be a large tx size for it to not confirm for a while with that kind of fee. Most players won't really notice a difference with paying 4 cents extra for the fee if they can play instantly, but it protects you a lot more. It also shouldn't affect the people that like small fees, since they can choose to wait for it to confirm.

[BitcoinBlackjack]

You could do what luckyb.it does and wait for it to confirm with a low fee, or have instant play with a fee of at least 0.0002BTC. Should stop most double spenders, as it needs to be a large tx size for it to not confirm for a while with that kind of fee. Most players won't really notice a difference with paying 4 cents extra for the fee if they can play instantly, but it protects you a lot more. It also shouldn't affect the people that like small fees, since they can choose to wait for it to confirm.

Correct me if I'm wrong, but aren't they able to double spend regardless of the fee amount simply by putting a higher fee for the same transaction before the confirmation hits?

[Arcteryx]

Never heard of anyone getting away doing this before as I am sure the casino sites have anti-fraud contingency plans in place so this doesn't happen when you put in a deposit on their site. If not, then their security department needs to be replaced with capable staff to code the proper script for the confirmations when they are coming in.

[Herbert2020]

interesting, but so far all the sites that i have played at are accepting 1 confirmation minimum, never seen 0 confirmation yet.

you can do a couple of things:
- accept 0 confirmation for small investments to lower the risk and lower the loss in case of fraud. and ask for 1 and more for bigger investments.
- also you can also check the fees that are included in the transaction or in other words check the transaction's priority to make sure it is high and going to be confirmed soon.

[Shibashi Dogemoto]

I don't think 1 confirmations will be a big problem... After all, i think most bitcoin users are used to wait for one confirmation when they use their coins in other places.

[adaseb]

Wow. Seems like cheaters are getting really smart these days with these scams. I guess the website needs to wait for at least 1 confirmation then.

[talkbitcoin]

this is strange i have not seen any place that accepts bitcoin with 0 confirmation and even if they do it is so rare and they only accept it with 0 confirmation if the transaction size is really small.

[joksim299]

this is strange i have not seen any place that accepts bitcoin with 0 confirmation and even if they do it is so rare and they only accept it with 0 confirmation if the transaction size is really small.

There are many places that accept 0 confirmation deposit. (NitrogenSports,Bitsler)

[Wendigo]

NitrogenSports has a 0 confirmation policy I think but they do manual auditing of any outgoing transactions so I don't think this kind of shit will fly under their radar probably you will be banned and your funds will be seized if you try this scheme. I think DirectBet allows 0 confirmations on their bet deposits as well but I haven't heard of anyone trying to exploit their system. These scams are probably best performed on casino sites as sportsbetting requires a lot of time for the events to finish.

[Sidas_Crew669]

I never thought that a deposit confirmation 0, has a pretty adverse impact on the owners of the site and I also do not think that there are people who can take advantage of this. I feel your actions to address this issue have been very correct, considering if it is not soon resolved so many gambling sites that will have the impact of this.

[DarkStar_]

You could do what luckyb.it does and wait for it to confirm with a low fee, or have instant play with a fee of at least 0.0002BTC. Should stop most double spenders, as it needs to be a large tx size for it to not confirm for a while with that kind of fee. Most players won't really notice a difference with paying 4 cents extra for the fee if they can play instantly, but it protects you a lot more. It also shouldn't affect the people that like small fees, since they can choose to wait for it to confirm.

Correct me if I'm wrong, but aren't they able to double spend regardless of the fee amount simply by putting a higher fee for the same transaction before the confirmation hits?

They could, but if the fee is high enough, it should be confirmed very quickly. I'm not sure how luckyb.it does it, maybe send one of the owners a PM. I was just stating what I knew. It also is a lot more risky if you put a high fee, which might repel some people that want to double spend. Maybe if a tx has a combination of decent fee/small tx size and small sized deposit, then you will accept it without a confirmation. From my playing at luckyb.it, when ever I use a fee of 0.0002, even before it's confirmed they send my payout to my address. Seems like it would be easily exploitable.

[BitcoinBlackjack]

You could do what luckyb.it does and wait for it to confirm with a low fee, or have instant play with a fee of at least 0.0002BTC. Should stop most double spenders, as it needs to be a large tx size for it to not confirm for a while with that kind of fee. Most players won't really notice a difference with paying 4 cents extra for the fee if they can play instantly, but it protects you a lot more. It also shouldn't affect the people that like small fees, since they can choose to wait for it to confirm.

Correct me if I'm wrong, but aren't they able to double spend regardless of the fee amount simply by putting a higher fee for the same transaction before the confirmation hits?

They could, but if the fee is high enough, it should be confirmed very quickly. I'm not sure how luckyb.it does it, maybe send one of the owners a PM. I was just stating what I knew. It also is a lot more risky if you put a high fee, which might repel some people that want to double spend. Maybe if a tx has a combination of decent fee/small tx size and small sized deposit, then you will accept it without a confirmation. From my playing at luckyb.it, when ever I use a fee of 0.0002, even before it's confirmed they send my payout to my address. Seems like it would be easily exploitable.

I'll send them a message and see what they do to protect themselves

[Slark]

The solution is simple. Lets keep 0 confirmation deposit as it is a nice feature to have. But instead put a restriction on a withdrawal -
Unless your deposit wasn't  confirmed  you can't withdraw it. It is as simple as that.

[Evildrum]

I really do not understand how double spending works,always presumed you need the funds in the wallet to actually send something and I have never canceled a transaction. Actually had no idea that this could be done are there threads on how this is done,so I know what to look out for in the future if I ever do end up in a potential situation like that?

[BitcoinBlackjack]

The solution is simple. Lets keep 0 confirmation deposit as it is a nice feature to have. But instead put a restriction on a withdrawal -
Unless your deposit wasn't  confirmed  you can't withdraw it. It is as simple as that.

The cheaters act like this:
Create account #1 -> deposit BTC -> they lose -> they double spend
Create account #2 -> deposit BTC -> they lose -> they double spend
Create account #3 -> deposit BTC -> they WIN -> they allow the transaction to go through -> transaction confirms -> they request a withdrawal

So in this case, we wouldn't allow accounts #1 and #2 to withdraw, but we WOULD allow account #3 to withdraw, since it has a confirmation. But it is still a cheater's account.
As you can see, it still does not help us because the cheaters are able to constantly create new accounts with different IPs and emails until they win.

[bitbaby]

Yours is not the first site it has happened too, the biggest sites have faced this problem and the solution you implemented is the best solution there is, one confirmation on a normal day should take on average 10 minutes and its same for everyone so gamblers have to wait that much to play at any casino.

Up to 1 BTC, 1 confirmation should suffice, over that you should wait for at-least 3 confirmations.

[Evildrum]

No one wants to help me understand how this works? Always hear about waiting for confirmations but never read how people are able to cancel a transaction?
Was thinking this should not be a issue but forgot about people being able to create infinite accounts.