Bitcoin Forum

https://cointelegraph.com/news/bitcoin-double-spend-spotted-in-the-wild/amp

Someone is trying to bring BTC price down as the transaction is showing as invalid
https://www.blockchain.com/btc/tx/9e19bc72f3b9bb23351311f88dc6f5c2e7a209a4fb0ad80b35d50f765e343e29

That's basically what a double spend is... The fact the outputs used as input for above transactions were also used for a different transaction, and this second transaction ended up in a block in the longest chain (the one with the most work) is the explanation of a double spend.

This being said, a double spend with an output with a fiat value of ~$20 is probably just a coincidence, not somebody deliberately trying to bring the price down.

I think what he means is whoever is writing the article and spreading this fake news is trying to bring down the price. There was no double spend, there was just a typical fork in the blockchain that got resolved and the other spend got orphaned on the losing fork. This isn't even a noteworthy occurrence yet it is being advertised as some monumental flaw in Bitcoin.

This wasn't a double spend as reported by most media articles that you see going around, as that was supposedly just the same coins from the same wallet being split during a blockchain reorganization (which is fairly frequent). This happens when two miners mine the same block, at the same time (essentially causing like a split in the blockchain) and then the subsequent miners who mine the next block in the sequence chose one of the pathways more than the other, causing it to win out and "being the dominant way to go".

The other history is considered irrelevant by the network. No new coins were accidentally added to the supply. Also, only one of the two transactions will be registered and considered as valid. Coindesk shows a possibility of what might have actually happened: https://www.coindesk.com/bitcoin-double-spend-that-never-happened


As long as only one of the different versions of the transaction is accepted, its all fine and dandy.

Stupidity of the people reporting this.

I am just blown away how someone not knowing how bitcoin works with regard to double spends and re-orgs can start stupid stuff like that can be ever taken seriously again.  BitMEX Research saying "It appears as if a small double spend of around..."[*1] One of the stupidest groups claiming to be experts, says something like that?  My heavens they don't even know what a double spend is. That isn't a double spend and yet their tweet says it is. A re-org and double spend are different things.

There was NO DOUBLE SPEND.  Something spent one way, then a re-org occurred and a different transaction is included in the other block is NOT a double spend.  Idiocy claiming to be insightful.

And they have the nerve to say "Filtering out the hype with evidence-based reports on the cryptocurrency ecosystem ".  LOL. Ludicrous.

And then they claim they didn't say:
"There was a stale Bitcoin block today, at height 666,833. SlushPool has beaten F2Pool in a race.

It appears as if a small double spend of around 0.00062063 BTC ($21) was detected"
and that someone else was to blame:



[*1]https://twitter.com/BitMEXResearch/status/1351856488252399618

No.

It would only be a double spend IF both transactions were included in the block chain.  They were not, one was included in one block that was then re-org'd out of existence and the RBF transaction replaced it.  Both transactions are not in the block chain, hence no double spend.

Multiple confirmations for large amounts (or even smaller) is important for reasons such as this.

What I wonder is....this has to have happened multiple times before. How is this news now? After so many years? As I'm sure people looking would have noticed it previously, but it somehow makes the news now? Was this a deliberate strategy to reduce the price by hurting the general concensus?

It is a pure and simple FUD. Read below,

https://www.cryptoglobe.com/latest/2021/01/bitcoin-did-not-experience-a-double-spend-the-blockchain-worked-as-intended/

Yahoo Finance says,


Ref: https://au.finance.yahoo.com/news/bitcoin-double-spend-never-happened-210834555.html

Case dismissed!

It happens all the time in the mempool with RBF.  This was essentially the same thing since there was a reorganization.   I don’t know if it has happened before, wouldn’t surprise me either way.

You just didn’t have idiots like BitMEX research using a phrase like they did. It was either stupidity on their part or idiocy in using a term improperly.

To be honest, I didn't do my own research and just went from what i had seen floating around without actually looking at the transactions, so i might have mislabeled what happened (it might have been an rbf, but i can no longer find the invalid transaction so i cannot verify). I personally feel this discussion is about semantics and 0.00062063 BTC simply isn't worth starting a discussion over. I know that the blockchain is actually satoshi's sollution for the double spend problem and nobody can actually get two transaction spending the same output into the chain with the most accumulated difficulty (well, they can't get them in a stale chain either, but who cares)...

For me, it was a non-issue anyways, but i'd still like to detail my rationale as to why i (mis)called this one a doublespend based on the very limited research i did on this specific occurrence.

I didn't initially use any sources, but for this rationale, i've used https://en.bitcoin.it/wiki/Irreversible_Transactions because, let's face it, sometimes it's easier to quote a well-known source than it is to start from scratch :)

source: https://en.bitcoin.it/wiki/Irreversible_Transactions

While it is true one cannot get two double spending transactions in the chain with the most difficulty, to my knowledge it IS possible to have 2 unconfirmed transactions spending the same unspent output floating around in the network node's mempools. So, in reality, those two (or more) unconfirmed transaction are double (or tripple, or quadriple) spending the same unspent output. It's only when one of the two (or more) transactions ends up in a block, the other one becomes invalid... Unless there is a re-org, in which case the "invalid" transaction could possibly end up in the chain with the most difficulty and make the initially "confirmed" transaction suddenly invalid. Which i tought was happening here, hence the term "double-spending" popped up.

source: https://en.bitcoin.it/wiki/Irreversible_Transactions

I assumed this was a case of a blockchain reorganisation in which a transaction double spending the same output as a transaction that was in the other chain happened and said double spending tx ended up in the reorged chain... I mean, it was only $22 worth of BTC (at the exchange rate at that time). This is the reason why i didn't look any deeper: for god's sake, it was $22... It was clearly an accident (or in this case, somebody probably increased the fee of an rbf transaction).

Yup, everything worked exactly as it should have worked (i never claimed otherwise). Yup your funds are safe. Yup, it's a big bowl of FUD... But two unconfirmed transactions can spend the same unspent output... They can not end up in the same chain, but as long as they're unconfirmed, they can be double-spending... A re-org can happen, and both the stale chain as the longest can contain a different transaction spending the same unspent output. Hence the terminology i used.