Has anybody ever successfully double spent?

[The Chainmaker]

And if so, is there a list of people that have gained from double spending and amounts that they were successful at double spending?

I am just wondering because lots of people talk about double spending being a major problem, yet I don't really see any cases of it.  Just wondering if I missed them.

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[Melbustus]

I have never heard of actually happening but the idea is that it would shatter the confidence crashing the coin.

No, the circumstances under which double-spends are theoretically possible are well-understood; a successful double-spend under such a circumstance wouldn't be particularly meaningful.

For example, a $10,000-equivalent double-spend was successfully issued during the March 2013 blockchain fork event: https://bitcointalk.org/index.php?topic=152348.0
The price rallied significantly in the subsequent month.

[Kluge]

Sure. Go ahead and accept BTC for payment and accept zero-conf transactions. Sell digital goods like Steam codes where the exchange is instant.

It doesn't happen very often because the market regularly prunes stupid people out.

ETA: No cheating by having the service check against the tx queue for double-spends.

[jonald_fyookball]

I have never heard of actually happening but the idea is that it would shatter the confidence crashing the coin.

double spend by a 51% attacker doing a multi block reorg would be confidence shattering.

double spend by a hacker on a 0 confirmation transaction, not so much.

[Omikifuse]

No. I'm not an overpowered guy that controls and/or can fool trusted bitcoin nodes.

[Tirapon]

There was a fork in the blockchain back in March 2013 I think, due to incompatibility between new and old versions of Bitcoin QT. During that period, I seem to remember there was a successful double spend against an exchange. The situation was dealt with very quickly and I think the double spend was reversed.

As far as I'm aware, there haven't been any major successful double spends of Bitcoin since then.

[medUSA]

For example, a $10,000-equivalent double-spend was successfully issued during the March 2013 blockchain fork event: https://bitcointalk.org/index.php?topic=152348.0
The price rallied significantly in the subsequent month.

I remember reading it when I first started with bitcoin. Didn't understand much of it at the time.

And if so, is there a list of people that have gained from double spending and amounts that they were successful at double spending?

The bitcoin nodes are so well linked. I think double spending on a healthy bitcoin network is extremely difficult. There is a page at blockchain.info on double spend attempts. I think none of them are successful:
https://blockchain.info/double-spends

[princesocapuyo]

That has to do with 51% attacks right? I haven't heard of any cases either. I did some research and there was a successful double-spend on 2013 (of course people already told you that lol) other than that nothing.

For example, a $10,000-equivalent double-spend was successfully issued during the March 2013 blockchain fork event: https://bitcointalk.org/index.php?topic=152348.0
The price rallied significantly in the subsequent month.

I remember reading it when I first started with bitcoin. Didn't understand much of it at the time.

And if so, is there a list of people that have gained from double spending and amounts that they were successful at double spending?

The bitcoin nodes are so well linked. I think double spending on a healthy bitcoin network is extremely difficult. There is a page at blockchain.info on double spend attempts. I think none of them are successful:
https://blockchain.info/double-spends

I don't really get the page you linked though, on some of them it says "spent" which means the transaction was successful? sorry I'm newb

[franky1]

There was a fork in the blockchain back in March 2013 I think, due to incompatibility between new and old versions of Bitcoin QT. During that period, I seem to remember there was a successful double spend against an exchange. The situation was dealt with very quickly and I think the double spend was reversed.

As far as I'm aware, there haven't been any major successful double spends of Bitcoin since then.

there have been no double spends of bitcoin.. EVER

there have been instances that services have given away DIFFERENT currencies multiple times, but there is no actual double spend of bitcoin. the fault is of service providers not interpreting transactions appropriately.

[Fernandez]

I don't think there have ever been double spending on Bitcoin. There has been case with altcoins which are easy to attack due to their low hashrate.

If Bitcoin is going to be attacked its going to be a coalition of big pools for whatever reasons. In that case everyone will get disrupted and it will be a huge event, and possibilities like this exist in all spheres of life.

[Sindelar1938]

There have been several well-documented attempts but never successfully as far as I am aware

[Omikifuse]

Question is: how could a Joe like me that has  0 hash power be able to double spend even with 0 confirmation transactions that sooner or later will be identified?

[hungergamespro132]

Question is: how could a Joe like me that has  0 hash power be able to double spend even with 0 confirmation transactions that sooner or later will be identified?

i was thinking about that too and found on google how to do it though i quit because i couldnt find any gambling sites that accept 0 confirms deposits and payouts instantly

[Lauda]

Question is: how could a Joe like me that has  0 hash power be able to double spend even with 0 confirmation transactions that sooner or later will be identified?

Well you can't technically make a double spent. You could however 'double spend' funds from a merchant in case of a bug in their software or something.

[Corenin]

i don't think anyone will tell this even if he has done it successfully
many people do this, or scam others with fake transactions

[Come-from-Beyond]

Has anybody ever successfully double spent?

Define "double spent", please. There are different definitions of this term and depending on what you are asking about the answer may be YES or NO.

[Crestington]

If you are talking about 0 confirmation transactions then it's rather easy to double spend. Send a transaction with no fee, then roll back your transactions and send the same transaction with a higher fee so it gets included into the Blockchain first, rejecting the first transaction. This only applies to accepting 0 confirmation transactions though, you would need a lot of mining power to try and get transactions with one or more confirmation through.

It just so happened that my first transaction I sent with Bitcoin was with no fee and was stuck for 4-5 days trying to get into BTC-e with no confirmations and so had to do something. The first transaction was left in perpetual limbo as 0 confirmations so technically it wasn't a double spend.

[calci]

And if so, is there a list of people that have gained from double spending and amounts that they were successful at double spending?

I am just wondering because lots of people talk about double spending being a major problem, yet I don't really see any cases of it.  Just wondering if I missed them.

I think in the old times yes. Blockchain actually has a list of all double spents that have occured till now.

[DannyHamilton]

Has anybody ever successfully double spent?

Define "double spent", please. There are different definitions of this term and depending on what you are asking about the answer may be YES or NO.

^^ This.  Very much this. ^^

A true double spend (where a previous transaction output is used as an input in two different transactions that are both permanently recorded in the blockchain) is impossible.  It never has happened. It never will happen.

However, people that don't understand the technical detais of how bitcoin works like to use the words "double spend" to describe a variety of scams that allow an attacker to fool their target into believing that they've received bitcoins that they never actually received.

So, if you are asking about a true double spend, then no, it hasn't ever happened.  It never will.

If you are asking about a scam where someone is tricked into believing that they've received bitcoins that they haven't due to the target's own misunderstanding about how bitcoin works, then yes.  That has happened many times.

[Kearney52]

double spant will cost so much money , no borning people will do this thing for bitcoin
but i think this will happen in altcoin