How to carry out a double spend using blocochain.info?

[Sarthak]

I just read dznut's post  and in the replies I heard a lot of people suggesting him to "double-spend"!

Here are my queries:

1) How do you carry out an double spend from blockchain.info? (Step by step guide)

2) Some sites like 999dice accept 0 confirmation deposit! Aren't they vulnerable to double-spending attacks?( keepinquiet tried double spending but got caught by the 999dice admin).

I will ask more If I need to know something more
Thanks!

[emrebey]

I just read dznut's post  and in the replies I heard a lot of people suggesting him to "double-spend"!

Here are my queries:

1) How do you carry out an double spend from blockchain.info? (Step by step guide)

2) Some sites like 999dice accept 0 confirmation deposit! Aren't they vulnerable to double-spending attacks?( keepinquiet tried double spending but got caught by the 999dice admin).

I will ask more If I need to know something more
Thanks!

1) that's not possible afaik. but there are tools available - you need your own wallet.

2) 0 confirmation deposits are vulnerable to double-spend. but, it's easy to catch for the admins :-)

[Sarthak]

2) 0 confirmation deposits are vulnerable to double-spend. but, it's easy to catch for the admins :-)

How do the admins catch them? Double interesting thing is far more interesting than I thought it is

[twister]

Double spends are not possible, if you think you'll be able to make money on 999dice and cash-out without any confirmations on your deposit then you're mistaken.

There are Gambling sites which allow 0 confirmation deposits but you can't cash-out until your deposit has reached 3 confirmations at-least.

[Sarthak]

See the personal text? There's written genius! I have another way to make money if double spend works! I don't have to withdraw

Edit:

I'm not sure about the sites to find detailed information but I usually find them on Bitcointalk so try to Google it.

They can be abused if you have some mining power. Send a transaction to the address with 0 fees then another to your own address also with 0 fees. Bet all the money that appears in your account if win then use the mining power to include the transaction sent to the address from 999dice and confirm it. If you lost, then confirm the other one.

Is this possible if I have mining power? This is not the idea I have though! If my deposit just shows up I make money No need for any wd

[twister]

No, I don't think thats possible. To do that one would need 51% Mining power. Only one of those tx might be included in the block and the other one gets dropped and you can't choose which one.

[emrebey]

See the personal text? There's written genius! I have another way to make money if double spend works! I don't have to withdraw

Edit:

I'm not sure about the sites to find detailed information but I usually find them on Bitcointalk so try to Google it.

They can be abused if you have some mining power. Send a transaction to the address with 0 fees then another to your own address also with 0 fees. Bet all the money that appears in your account if win then use the mining power to include the transaction sent to the address from 999dice and confirm it. If you lost, then confirm the other one.

Is this possible if I have mining power? This is not the idea I have though! If my deposit just shows up I make money No need for any wd

if you have %51 of network, you would have probably wouldn't interest in double spending.

[dznuts85]

I just read dznut's post  and in the replies I heard a lot of people suggesting him to "double-spend"!

Here are my queries:

1) How do you carry out an double spend from blockchain.info? (Step by step guide)

2) Some sites like 999dice accept 0 confirmation deposit! Aren't they vulnerable to double-spending attacks?( keepinquiet tried double spending but got caught by the 999dice admin).

I will ask more If I need to know something more
Thanks!

1) that's not possible afaik. but there are tools available - you need your own wallet.

2) 0 confirmation deposits are vulnerable to double-spend. but, it's easy to catch for the admins :-)

what tools is it? i want to try double spending coz some of my coins is stuck and not confirming for almost 2 weeks now

[CIYAM]

i want to try double spending coz some of my coins is stuck and not confirming for almost 2 weeks now

If a pool is using modified software then it is entirely possible they could decide to reject txs with zero fees and accept an alternative tx spending the same UTXOs that does have fees (although I'm not sure if any pool is actually doing this at the moment).

You would have to be able to send such a "replacement" tx directly to the pool though as any standard nodes that have seen the first tx will simply reject the second as a double-spend attempt and not forward it to their other peers.

If your coins are "stuck" this is typically due to having paid zero tx fees and the UTXOs are either of too low value or age to qualify to be included in a block (if you are running an old client it might keep sending out the invalid tx so you might want to look into how to get rid of the tx from your wallet if this is the case).

Also the online gambling sites are not stupid enough to lose money from unconfirmed txs so this approach is not going to be a method to make money from them (it is only most likely to succeed for some small physical purchase if a store decides to accept 0 confirmations).

[Skeksis]

Op, so you're actually trying to ask people to help you figure out how to scam the system? Shame on you.

[yeponlyone]

No, I don't think thats possible. To do that one would need 51% Mining power. Only one of those tx might be included in the block and the other one gets dropped and you can't choose which one.

You can do that attack with any amount of hashpower as long as the merchant don't require large amount of confirmation and you mine the next few/next block. but of course, the probability to succeed is lower if your hashrate is lower than 51%.

[twister]

No, I don't think thats possible. To do that one would need 51% Mining power. Only one of those tx might be included in the block and the other one gets dropped and you can't choose which one.

You can do that attack with any amount of hashpower as long as the merchant don't require large amount of confirmation and you mine the next few/next block. but of course, the probability to succeed is lower if your hashrate is lower than 51%.

So what he is saying, is that possible?

See the personal text? There's written genius! I have another way to make money if double spend works! I don't have to withdraw

Edit:

I'm not sure about the sites to find detailed information but I usually find them on Bitcointalk so try to Google it.

They can be abused if you have some mining power. Send a transaction to the address with 0 fees then another to your own address also with 0 fees. Bet all the money that appears in your account if win then use the mining power to include the transaction sent to the address from 999dice and confirm it. If you lost, then confirm the other one.

Is this possible if I have mining power? This is not the idea I have though! If my deposit just shows up I make money No need for any wd

I mean if one can do this, he won't lose a bet as whatever bet he looses, he will cancel that Tx by pushing the other one through?

[Sarthak]

Doublespending doesn't essentially mean its for bad! I just asked for educational purpose!

I never understood these technical things about bitcoins! Perhaps, this is my first post on the technical support section!
And using it for bad requires a lot of technical information to be acquired to prevent being traced!

Conclusion: This is just for edu. purpose! If you don't believe me, believe what you believe

[notlist3d]

No, I don't think thats possible. To do that one would need 51% Mining power. Only one of those tx might be included in the block and the other one gets dropped and you can't choose which one.

You can do that attack with any amount of hashpower as long as the merchant don't require large amount of confirmation and you mine the next few/next block. but of course, the probability to succeed is lower if your hashrate is lower than 51%.

So what he is saying, is that possible?

See the personal text? There's written genius! I have another way to make money if double spend works! I don't have to withdraw

Edit:

I'm not sure about the sites to find detailed information but I usually find them on Bitcointalk so try to Google it.

They can be abused if you have some mining power. Send a transaction to the address with 0 fees then another to your own address also with 0 fees. Bet all the money that appears in your account if win then use the mining power to include the transaction sent to the address from 999dice and confirm it. If you lost, then confirm the other one.

Is this possible if I have mining power? This is not the idea I have though! If my deposit just shows up I make money No need for any wd

I mean if one can do this, he won't lose a bet as whatever bet he looses, he will cancel that Tx by pushing the other one through?

It sounds like it might be possible.  But it would not be worth it.  It will be easy to detect double spend after.   

And eventually chances are you will be caught, or the site will change requiring confirmation if abuse is bad enough.  Also it's not worth getting a scammer tag which will follow you and ruin a account.

[Sarthak]

Actually If it worked the method was to bet with a ref account of the same player and wager enough and withdraw the ref. commission from other account

This double spend is interesting and also hard! So I am leaving this thing from now..

[ranochigo]

No, I don't think thats possible. To do that one would need 51% Mining power. Only one of those tx might be included in the block and the other one gets dropped and you can't choose which one.

You can do that attack with any amount of hashpower as long as the merchant don't require large amount of confirmation and you mine the next few/next block. but of course, the probability to succeed is lower if your hashrate is lower than 51%.

So what he is saying, is that possible?

See the personal text? There's written genius! I have another way to make money if double spend works! I don't have to withdraw

Edit:

I'm not sure about the sites to find detailed information but I usually find them on Bitcointalk so try to Google it.

They can be abused if you have some mining power. Send a transaction to the address with 0 fees then another to your own address also with 0 fees. Bet all the money that appears in your account if win then use the mining power to include the transaction sent to the address from 999dice and confirm it. If you lost, then confirm the other one.

Is this possible if I have mining power? This is not the idea I have though! If my deposit just shows up I make money No need for any wd

I mean if one can do this, he won't lose a bet as whatever bet he looses, he will cancel that Tx by pushing the other one through?

It sounds like it might be possible.  But it would not be worth it.  It will be easy to detect double spend after.   

And eventually chances are you will be caught, or the site will change requiring confirmation if abuse is bad enough.  Also it's not worth getting a scammer tag which will follow you and ruin a account.

You could create alternate accounts and use VPNs to hide your identity. That's what happened with primedice (https://bitcointalk.org/index.php?topic=208986.msg7208301#msg7208301) and (http://www.reddit.com/r/Bitcoin/comments/1qqmr4/ghashiocexio_and_doublespending_against_betcoin/). It is fairly easy to abuse if you think about it. Even if onchain gambling site include your outputs in the payout transaction, it can still be manipulated.

[twister]

No, I don't think thats possible. To do that one would need 51% Mining power. Only one of those tx might be included in the block and the other one gets dropped and you can't choose which one.

You can do that attack with any amount of hashpower as long as the merchant don't require large amount of confirmation and you mine the next few/next block. but of course, the probability to succeed is lower if your hashrate is lower than 51%.

So what he is saying, is that possible?

See the personal text? There's written genius! I have another way to make money if double spend works! I don't have to withdraw

Edit:

I'm not sure about the sites to find detailed information but I usually find them on Bitcointalk so try to Google it.

They can be abused if you have some mining power. Send a transaction to the address with 0 fees then another to your own address also with 0 fees. Bet all the money that appears in your account if win then use the mining power to include the transaction sent to the address from 999dice and confirm it. If you lost, then confirm the other one.

Is this possible if I have mining power? This is not the idea I have though! If my deposit just shows up I make money No need for any wd

I mean if one can do this, he won't lose a bet as whatever bet he looses, he will cancel that Tx by pushing the other one through?

It sounds like it might be possible.  But it would not be worth it.  It will be easy to detect double spend after.   

And eventually chances are you will be caught, or the site will change requiring confirmation if abuse is bad enough.  Also it's not worth getting a scammer tag which will follow you and ruin a account.

You could create alternate accounts and use VPNs to hide your identity. That's what happened with primedice (https://bitcointalk.org/index.php?topic=208986.msg7208301#msg7208301) and (http://www.reddit.com/r/Bitcoin/comments/1qqmr4/ghashiocexio_and_doublespending_against_betcoin/). It is fairly easy to abuse if you think about it. Even if onchain gambling site include your outputs in the payout transaction, it can still be manipulated.

Yeah but it can't go on forever, you might get away with it once or twice but then site owners will notice it when they see that all the losing bets are getting dropped and winning once are getting through.

And when that happens they will either make rule of no '0' fee bets or will not allow bets until they have at-least reached 1 confirmation.

[dznuts85]

i want to try double spending coz some of my coins is stuck and not confirming for almost 2 weeks now

If a pool is using modified software then it is entirely possible they could decide to reject txs with zero fees and accept an alternative tx spending the same UTXOs that does have fees (although I'm not sure if any pool is actually doing this at the moment).

You would have to be able to send such a "replacement" tx directly to the pool though as any standard nodes that have seen the first tx will simply reject the second as a double-spend attempt and not forward it to their other peers.

If your coins are "stuck" this is typically due to having paid zero tx fees and the UTXOs are either of too low value or age to qualify to be included in a block (if you are running an old client it might keep sending out the invalid tx so you might want to look into how to get rid of the tx from your wallet if this is the case).

Also the online gambling sites are not stupid enough to lose money from unconfirmed txs so this approach is not going to be a method to make money from them (it is only most likely to succeed for some small physical purchase if a store decides to accept 0 confirmations).

how is that sending a replacement transaction? sorry i cant understand it clearly for i am not a techy guy

[tspacepilot]

i want to try double spending coz some of my coins is stuck and not confirming for almost 2 weeks now

If a pool is using modified software then it is entirely possible they could decide to reject txs with zero fees and accept an alternative tx spending the same UTXOs that does have fees (although I'm not sure if any pool is actually doing this at the moment).

You would have to be able to send such a "replacement" tx directly to the pool though as any standard nodes that have seen the first tx will simply reject the second as a double-spend attempt and not forward it to their other peers.

If your coins are "stuck" this is typically due to having paid zero tx fees and the UTXOs are either of too low value or age to qualify to be included in a block (if you are running an old client it might keep sending out the invalid tx so you might want to look into how to get rid of the tx from your wallet if this is the case).

Also the online gambling sites are not stupid enough to lose money from unconfirmed txs so this approach is not going to be a method to make money from them (it is only most likely to succeed for some small physical purchase if a store decides to accept 0 confirmations).

how is that sending a replacement transaction? sorry i cant understand it clearly for i am not a techy guy

If I read him right he's suggesting that if your your coins are stuck because some paricular node has rejected your tx attempt and isn't forwarding it then you may be able to "fix" it by sending another tx with a proper fee.  The idea is that first tx attempt fades into oblivion and the second one gets hashed into a block.  "replacement" because the second attempt is meant to replace the first.

It also seems to me that you could possibly simply replay the blockchain in a fresh wallet after importing your keys.  The fresh wallet wouldn't know about the stuck tx unders the assumption that it wasn't broadcast to the network.  I may be mistaken tho.