Bitcoin Toss - Flip a coin and win double your entry! - page 4.

randomguy7

hero member

Activity: 527

Merit: 500

Quote from: FreeMoney on April 26, 2011, 09:47:39 AM

You can't use coins from a generate tx for 120 blocks.

I know but thats not necessary, the coins used to play aren't those which are generated by the found block, they're just some coins. The block is only used to undo the transaction used to send coins to the game owner. This works because the bet will be already played before somebody else can calculate the transaction into the blockchain (at least most of the times).

edit: typos removed

FreeMoney

legendary

Activity: 1246

Merit: 1016

Strength in numbers

Quote from: randomguy7 on April 26, 2011, 07:13:46 AM

I don't find the source (I read about it somewhere here in the forum) but I think it works like this:
The attacker has to mine for a valid block for this. When he found one, he must not yet submit it to the network. He sends you the coins and plays on your site. When he won, he's fine, no need to perform the attack (wouldn't be possible as you delay the payouts). When he lost, he's using the block he already found and adds a transaction to it to send the coins you currently 'have' with 0 confirmations to another address (one controlled by the attacker). He then submits the block to the net. Your coins are gone.

This of course requires that nobody else finds a block while the attack is performed, but there's a very good propability for this to not happen (I assume playing a bet on your site doesn't require much time, maybe not even a minute).

You can't use coins from a generate tx for 120 blocks.

randomguy7

hero member

Activity: 527

Merit: 500

I don't find the source (I read about it somewhere here in the forum) but I think it works like this:
The attacker has to mine for a valid block for this. When he found one, he must not yet submit it to the network. He sends you the coins and plays on your site. When he won, he's fine, no need to perform the attack (wouldn't be possible as you delay the payouts). When he lost, he's using the block he already found and adds a transaction to it to send the coins you currently 'have' with 0 confirmations to another address (one controlled by the attacker). He then submits the block to the net. Your coins are gone.

This of course requires that nobody else finds a block while the attack is performed, but there's a very good propability for this to not happen (I assume playing a bet on your site doesn't require much time, maybe not even a minute).

Alex Beckenham

full member

Activity: 154

Merit: 100

Quote from: randomguy7 on April 26, 2011, 06:38:45 AM

Thats basically a good idea, but I think it's possible to cheat:
As far as I know, it's possible (with some effort) to undo the spendings with 0 confirmations (I forgot about the name of that attack and how it's done in detail). You delay the payout of winnings but people could still cheat you by undoing the payments for the games they lost.

I'd be interested to hear about that type of attack. I think even mybitcoin.com 'accepts' payments on 0/unconfirmed and sends postback data to merchants immediately.

randomguy7

hero member

Activity: 527

Merit: 500

Thats basically a good idea, but I think it's possible to cheat:
As far as I know, it's possible (with some effort) to undo the spendings with 0 confirmations (I forgot about the name of that attack and how it's done in detail). You delay the payout of winnings but people could still cheat you by undoing the payments for the games they lost.

Alex Beckenham

full member

Activity: 154

Merit: 100

Quote from: randomguy7 on April 25, 2011, 07:20:52 PM

...another flip-a-coin like game (https://bitcointalksearch.org/topic/experiences-about-doubletroublebitcoinbetcom-3862), it could even be the some guy with a new forum account...

I don't own that one by the way. The reason I decided it'd be worth copying the concept is that I don't like the way they make you wait a million years between paying and playing. I prefer the long wait to be on the other end of the game.

Alex Beckenham

full member

Activity: 154

Merit: 100

Quote from: sat0pi on April 26, 2011, 01:30:55 AM

Quote from: Alex Beckenham on April 26, 2011, 01:22:40 AM

The payment is showing in my client as 0/offline? -240.00

It'll get to you eventually.

That's strange... Wonder if that is a problem on my end or yours. I do have an abnormally low number of connections at the moment (only 8, I usually have like 30+). Ah well, it'll make it through as you say. Never seen that message before though. Anyone more knowledgeable than I care to share what it means?

EDIT: Never mind... Did some Googling and figured out what it was. I think it's an issue on your end doood, but it should resolve itself eventually.

EDIT 2: Showing in my client as 0/unconfirmed... All should be well. Thanks again doood. bitcoin = best community ever.

Yeah straight after my last post, I restarted my client and it was then listed as 0/unconfirmed... so I guess the 'offline' error was on my end.

sat0pi

newbie

Activity: 38

Merit: 0

Quote from: Alex Beckenham on April 26, 2011, 01:22:40 AM

The payment is showing in my client as 0/offline? -240.00

It'll get to you eventually.

That's strange... Wonder if that is a problem on my end or yours. I do have an abnormally low number of connections at the moment (only 8, I usually have like 30+). Ah well, it'll make it through as you say. Never seen that message before though. Anyone more knowledgeable than I care to share what it means?

EDIT: Never mind... Did some Googling and figured out what it was. I think it's an issue on your end doood, but it should resolve itself eventually.

EDIT 2: Showing in my client as 0/unconfirmed... All should be well. Thanks again doood. bitcoin = best community ever.

Alex Beckenham

full member

Activity: 154

Merit: 100

Quote from: sat0pi on April 26, 2011, 01:06:39 AM

Not seeing the 240 in my client yet

The payment is showing in my client as 0/offline? -240.00

It'll get to you eventually.

sat0pi

newbie

Activity: 38

Merit: 0

Quote from: Alex Beckenham on April 26, 2011, 12:59:49 AM

240 sent...

Deposit addresses are definitely for one-time use. You should be getting a new one each time you play.

I'll write a warning about that on the site...

Awesome. Very respectable, doood... thanks so much! Not seeing the 240 in my client yet, but I'm sure it will appear soon enough. I'll let you know when I receive it just to confirm. Will definitely try out your site again more responsibly (and correctly) later on.

Thanks,
sat0pi

Alex Beckenham

full member

Activity: 154

Merit: 100

240 sent...

Deposit addresses are definitely for one-time use. You should be getting a new one each time you play.

I'll write a warning about that on the site...

sat0pi

newbie

Activity: 38

Merit: 0

doood, that's very generous of you... I can assure you I did in fact lose 11 times in a row though, I can send you a screenshot of my client if you want. Tongue

I was wondering if it was because I was using the same address every time and it was counting as the same session or something, but I didn't try a different address to see if that mattered... I am not sure what my id was. If you aren't seeing anything else other than that as 10 losses in a row though, that must be me.

14GjvZk1GqqAjKQNaJdur3jL2PzjdH3crf is a new address if you feel like being so kind as to refund me. I understand if you do not want to, though... it is your business after all. Just seemed strange that I would lose that many times in a row which is a sub 1% chance. Surely I can't be that "lucky", but who knows. Tongue

On a side note, the site is done really well... would love to see the source code. Grin

Thanks,
sat0pi

Alex Beckenham

full member

Activity: 154

Merit: 100

Thanks for the kind words.

There will absolutely be no other refunds from this point.

sat0pi: send me a new address if you like.

bitlotto

hero member

Activity: 672

Merit: 500

BitLotto - best odds + best payouts + cheat-proof

Quote from: Alex Beckenham on April 25, 2011, 08:59:40 PM

...I'll send you back 240...

There are few like you doood!! My respect for you went way up! Grin

FreeMoney

legendary

Activity: 1246

Merit: 1016

Strength in numbers

Repaying losses seems extremely generous to me, but you should make sure you don't give others the idea that they can freeroll you.

FreeMoney

legendary

Activity: 1246

Merit: 1016

Strength in numbers

Quote from: Alex Beckenham on April 25, 2011, 10:07:04 PM

Quote from: FreeMoney on April 25, 2011, 09:59:17 PM

Quote from: Alex Beckenham on April 25, 2011, 09:25:26 PM

Quote from: sat0pi on April 25, 2011, 06:28:58 PM

Lost 10 times in a row. That's not very likely, so I'm not sure how fair this is.

Were you ID 2?

That user looks like it's just hit refresh over and over again instead of starting each game from the start.

Wait, does that somehow let you play with the same result over and over?

No, it doesn't... refreshing is pointless... I can however see it in the logs.
It's the only thing I can see that even remotely looks like 10 losses in a row.

Ah, of course he could have gone out for a smoke and someone else played a few in between.

Alex Beckenham

full member

Activity: 154

Merit: 100

Quote from: FreeMoney on April 25, 2011, 09:59:17 PM

Quote from: Alex Beckenham on April 25, 2011, 09:25:26 PM

Quote from: sat0pi on April 25, 2011, 06:28:58 PM

Lost 10 times in a row. That's not very likely, so I'm not sure how fair this is.

Were you ID 2?

That user looks like it's just hit refresh over and over again instead of starting each game from the start.

Wait, does that somehow let you play with the same result over and over?

No, it doesn't... refreshing is pointless... I can however see it in the logs.
It's the only thing I can see that even remotely looks like 10 losses in a row.

FreeMoney

legendary

Activity: 1246

Merit: 1016

Strength in numbers

Quote from: Alex Beckenham on April 25, 2011, 09:25:26 PM

Quote from: sat0pi on April 25, 2011, 06:28:58 PM

Lost 10 times in a row. That's not very likely, so I'm not sure how fair this is.

Were you ID 2?

That user looks like it's just hit refresh over and over again instead of starting each game from the start.

Wait, does that somehow let you play with the same result over and over?

bitlotto

hero member

Activity: 672

Merit: 500

BitLotto - best odds + best payouts + cheat-proof

Quote from: randomguy7 on April 25, 2011, 07:20:52 PM

Personally, I'm done with gambling at sites which don't give me PROVE that they don't rip me off.

Must mean you entered BitLotto then? LOL. Wink

(It's pretty much impossible for me to fake anything.)

Alex Beckenham

full member

Activity: 154

Merit: 100

Quote from: sat0pi on April 25, 2011, 06:28:58 PM

Lost 10 times in a row. That's not very likely, so I'm not sure how fair this is.

Were you ID 2?

That user looks like it's just hit refresh over and over again instead of starting each game from the start, which surely doesn't count as 10 losses in a row.

Topic: Bitcoin Toss - Flip a coin and win double your entry! - page 4. (Read 17099 times)