Bitcoin Forum

Not sure what happened here but I sent .1 coins  on Sat Oct 17 at 3:57a. Then somehow its showing another transaction for the same amount to the same address at 4:25a.. I didn't initiate this transaction. It is now 3 days later and it still hasn't been confirmed. Can anyone tell me whats going on here and how/can I get my coins back ?
Heres the transaction summary:

A conflicting transaction has been detected in our memory pool. The transaction hash displayed below may change.
You Sent

0.1001 BTC ($ 27.07)

Value at time of transaction $ 27.18

Hash
bd4ead5dece3a6472bfb26762d419f292d298445276f505a654ecc0dd6134c4b
Sent Time
2015-10-17 09:25:57
Confirmations
Unconfirmed Transaction!
Double Spend
No Double Spend Detected
Transaction Fee
0.0001 BTC

The problem is the transaction malleability attack, which will only change the txid of the transaction. It essentially duplicates your transaction but with a different txid so it is regarded as a separate transaction and thus a double spend by the network. Only one of those transactions will be confirmed though. It looks like the malleated transaction was the confirmed one. Its txid is 5c30bffebfdc8733884943551596bee2fb1faea063d675a456cac3e6470f224c.

Thanks for your help. So is there a chance of me getting the coin back? or will the transaction eventually go through?

The transaction you sent will never confirm because the malleated version of it has already confirmed, thus making your transaction an invalid double spend. However, your coin has already confirmed and is spendable since the malleated version did confirm. The coins in a malleated transaction will always go to where it is supposed to since the attacker cannot change the inputs or outputs without rendering the transaction invalid.

what is this ?
i see at your address
 Warning! this bitcoin address contains transactions which may be double spends. You should be extremely careful when trusting any transactions to or from this address.

the person I sent the coins to has received .1 so who has the other .1?

I don't know? What should I do? Why am I seeing this? Does this happen often?  Should I shut down this wallet and start a new one?

Technically, that person does, but that transaction is useless. It cannot be spent from and just takes up space. Everything is exactly how you intended it, except that there happens to be an extra transaction floating around. You can get rid of it from your wallet, but we will need to know what wallet you are using.

Just ignore the malleability attack, it doesn't really change anything. You sent the same coins twice to the same person, the second transaction confirmed, so he still got the money. All in all, just ignore the double spend, its like it never happened.

Blockchain staff had to check the fake txid manuallyfgoing through all transactions and. Delete the record so it does takes time.. Mine take around 3-4 days lol

it is not done manually, all unconfirmed transactions will be dropped automatically by the memory pool if still not confirmed for 2-3 days AFAIK

hemmm maybe yess

No. Just no. Ignore ^ comment. The malleability attacks has nothing to do with whether you're personally compromised or not. Your wallet is fine, its something to do that is completely unrelated.

https://www.cryptocoinsnews.com/bitcoin-attack-coinkite-reports-malleability-attack-urges-caution/
Etc, its not really related to you. It doesn't really change anything.

It's not like it never happened because my coins are gone and I spent twice as much for something.

Blockchain

No, that is not true. You did not spend twice as much, your spent exactly the same amount. One of the transactions is useful, it is confirmed and can be didn't fun. The other is completely and absolutely useless. It is unconfirmed and will remain that way forever. Your balance does not change except for the amount you wanted to spend.

Just wait a few days and the transaction should disappear. Blockchain.info will automatically remove the transaction from their database when it remains unconfirmed for too long and that it is also a double spend.

No, as i'm saying, ignore them, they don't change anything. You sent the same coins twice to the same person. Not different coins each time. You did not spend 0.2. You only spent 0.1. Just ignore the malleability'd double spend. In all cause an effect, you can safely pretend they don't exist, because they don't actually do anything.

it's not like you spent it twice, it's just that one can be called as a "fake spent" it has no value, it will sit there like a dust

i was in the same boat with a payment from a faucet, not a dust payment, but a reasonable payment, it come two time, but the first was with the "?" and remained there forever

Let me give it a shot at explaining what happened.

You create a TX (A) that send 0.1 BTC to someone else. After you broadcasted it to the network. Someone else - lets call her Eve - modified your transaction slightly. Eve made a copy of the TX and gave it a different ID. Instead of A there is now also a TX A' that uses the same coins and sends them to the same person, but has a differnet name (TX ID)

A or A' can confirm, but never both, that would be a true double spend. Bitcoin was design to avoid true double spends, they can at best only exist in an unconfirmed state. This is the very basis of bitcoin. Your wallet provider (blockchain.info I assume from the above - B for short) however has to deal with unconfirmed transactions somehow to update your balance before a TX is confirmed. B has to handle A and A' and does so in the worst possible way. B handles A and A' as entirely different transactions that use entirely different coins.

That is why your balance is shown wrong, while on the blockchain you did not lose coins and the person you send them to received them without issues. Other wallets handle this better, e.g. I currently have a modified TX in my bitcoin core wallet. It shows up under the transactions as "conflicted" and is not part of the balance (not even of the unconfirmed). Its a bit annoying, but I can remove it myself with a simple command. Other wallets will have to update in order to deal with this somehow.

All you can do now is complain to blockchain.info and consider switching to a different wallet. Not because your wallet was compromised, but because blockchain.info is offering bad service.

Opel everything is explained above. Let me just add that you need to change a wallet. Blockchain.info wallet is the most prone to these malleability attacks and if you have used some other wallet, you wouldn't have this issue at the moment.

Change a wallet and stay away from online wallets if you possibly can.

So the .1 is still in my wallet? And my stated balance is incorrect?

The 0.1 you wanted to send was sent. And if your balance deducted 0.2 (which it probably did) then it is wrong.

reply it did subtract the .1 from my stated balance... so when i get to 0 will there still be a withdrawable .1 ? Or what do I need to do to get that .1 available to me?

The .1 will still be available. Blockchain.info will just show your balance as negative until they drop the unconfirmed transaction

ok thanks for taking the time to help me with this, I really appreciate it!

namaste