[RESOLVED] Dangerous situation with unconfirmed transactions!

[Perlover]

Hi,

I am waiting money from this transaction

https://blockchain.info/tx/7a61556699cf0fa79ce974966f9692cf0dc9a0fc1937ee08e9f1857e3e8cfc15

I got this money as payment
But if you will see - there is (U) output

The reseller with address 1JHif33UQGNkApimhtXaxvNJvwaULLZT1v paid to me. I work with them and they are ok.
But i am sure that they uses blockchain.info wallet and reuse address (i think same because they can comment transactions in blockchain.info)

But there very very dangerous situation.
There is very long chain from unconfirmed transactions:

https://blockchain.info/tx-index/69901819/0
https://blockchain.info/tx-index/69903207/1
https://blockchain.info/tx-index/69900458/1
https://blockchain.info/tx-index/69899816/1
https://blockchain.info/tx-index/69897027/1
https://blockchain.info/tx-index/69898025/1
https://blockchain.info/tx-index/69895266/1
https://blockchain.info/tx-index/69893186/1
https://blockchain.info/tx-index/69893825/1
https://blockchain.info/tx-index/69889516/1
https://blockchain.info/tx-index/69888701/1
https://blockchain.info/tx-index/69888152/1
https://blockchain.info/tx-index/69888148/0
https://blockchain.info/tx-index/69887337/1
https://blockchain.info/tx-index/69887286/0
https://blockchain.info/tx-index/69888019/1
https://blockchain.info/tx-index/69887997/0
https://blockchain.info/tx-index/69887218/0
https://blockchain.info/tx-index/69888019/1
https://blockchain.info/tx-index/69888019/0

But the root of all problems is this transaction:

https://blockchain.info/tx-index/69887997/0

It was sent (6 hours ago!) with very small value with zero comissions and has small value (0.0088)

But somebodies after these transactions spent these money by sending next transactions in bitcoin pool.
Miners don't take this zero-fee transaction for block
But from this small transaction many many other transactions are depended (with sums more more bigger than root transaction)!

If owner of this spent money (https://blockchain.info/tx-index/69887997/0) will want to make now double-spending (now with non-zero fee for example) - IT WILL BE BOOM! It's very easy to make as 'sweep money' for example, if address is cool storage for example.

My reseller thinks that i got money. They pay through blockchain.info wallet.
It's not criminal - to send chain of transactions in pool before includeing these in block.
This allows you to make multiple payments from a mobile wallet without waiting to confirmation.

But if it depends from multiply wallets and resellers - it's very dangerous!

I think a decision may be depend only from miners. But theirs software don't take zero-fee transactions a long time.
Now my money and other ones depend from one very small transaction! And i could not to do something against from this

Partly, i think, it's problem is caused by improving wallet software - to allow spend money from transaction which are in only current pool not in block. It would work fine if only not wishes of miners to take transactions with non-zero fee.

[shorena]

Transactions without fees get confirmed all the time, they just take longer.
Idiots like the person behind this are the reason why you should never accept a TX without at least X confirmations where X is > 0.

They might confirm within a week or two.

[shorena]

Transactions without fees get confirmed all the time, they just take longer.
Idiots like the person behind this are the reason why you should never accept a TX without at least X confirmations where X is > 0.

They might confirm within a week or two.

Not necessarily - I had some issues in the past where I got dust sent to my address that I utilize with Blockchain causing me so "bloat".  I then sent some BTC based on the regular fees (not the bloated size) to a friend and it would not confirm, after 4 days of not confirming it came back to me, had this happened where he sent me something on 0 confirms I would have prospered.

"it came back to me" is how blockchain.info handles it. If you use bitcoin core it will broadcast the transcation until it gets confirmed. Given enough time its priority will be high enough and the TX will get confirmed. 1 BTC and 1 day waiting is fine for a feeless TX. In this case a little over 1000 days should be enough.

This is not practical granted, but I dont see a reason for panic as the OP seems to. Just dont accept a TX as paid unless there is a confirmation (more than 1 for higher values TX). If this would be a local cash deal, Id be gone with my money allready and would never trade with that person again.


Edit: I wonder if its something like this [1]

[1] https://bitcointalk.org/index.php?topic=854655.0

[Perlover]

Idiots like the person behind this are the reason why you should never accept a TX without at least X confirmations where X is > 0.

I think there behind many persons. And as i understand they only use last freshed wallet software.
My reseller uses blockchain.info online wallet as i think (he can attach comments to transactions - this feature only for online blockchain.info wallets). So first bad bidder - online blockchain.info wallet.
I saw what mobile wallets (Bitcoin Wallet for Android) can spent (create & broadcast transaction) money from unspent outputs of other transactions.
It normal behaviour if i have Bitcoin Wallet and do some serial payments.

In anyway this situation undermines trust to the Bitcoin for users.
I know how the Bitcoin works and i can understand and describe problem, i can wait and post here messages.
But if a payment will be got by other not-well-known bitcoin user?

I think this problem from miner software. The miner software could be take this zero-fee transaction as priority because many other transactions are based from it (with non zero fee!). As do you think?

[amaclin]

Would you like me to fix problem with stuck tx https://blockchain.info/tx/7f6b37f6190a89b6f5e59329d7544f9627b6fd6e3c505d3058922ecce7a31669 ?

I am not owner of one of these addresses, but I can help

[Perlover]

Would you like me to fix problem with stuck tx https://blockchain.info/tx/7f6b37f6190a89b6f5e59329d7544f9627b6fd6e3c505d3058922ecce7a31669 ?

I am not owner of one of these addresses, but I can help

Are you miner?

P.S. I don't want to resolve problem by manual methods.
No, please don't do something. I want to see how this problem will be resolved without manual actions.

[Perlover]

As i think the problem lies elsewhere.
What happens if owner of address 1BRiSksEx7wioajqneij9Q6cvZFRDBUwgW will want to make double spending now?
It can be done very easy. Enough install secret key in other wallet and make transaction with non zero fee. Miners will take new transactions quickly and many many other transactions to be depend from this will collapse...

[amaclin]

Are you miner?

No. But I can "push" this transaction to a pool an it will be mined in reasonable time.
And all followed txs wil be mined also

I also can try to push malled transaction (this case is not guaranteed). And all followed transactions will be invalid and not mined

P.S. I don't want to resolve problem by manual methods.
No, please don't do something. I want to see how this problem will be resolved without manual actions.

OK, I will not do anything. Your choice.

[amaclin]

As i think the problem lies elsewhere.
What happens if owner of address 1BRiSksEx7wioajqneij9Q6cvZFRDBUwgW will want to make double spending now?

All followed transactions will become orphans and will non confirm forever

It can be done very easy. Enough install secret key in other wallet and make transaction with non zero fee. Miners will take new transactions quickly and many many other transactions to be depend from this will collapse...

It is not a bug. It is a feature of bitcoin protocol.

[Perlover]

I also can try to push malled transaction (this case is not guaranteed). And all followed transactions will be invalid and not mined

What is this (malled transaction)?
Peers can take your transaction only if it's valid. But this problem transaction is not your and you cannot make fake double-spending unless you have private key for address 1BRiSksEx7wioajqneij9Q6cvZFRDBUwgW

[Perlover]

It is not a bug. It is a feature of bitcoin protocol.

I know, i didn't talk about this as about bug

[amaclin]

I also can try to push malled transaction (this case is not guaranteed). And all followed transactions will be invalid and not mined

What is this (malled transaction)?

https://en.bitcoin.it/wiki/Transaction_Malleability

Peers can take your transaction only if it valid. But problem transaction is not your and you cannot make fake double-spending unless you have private key for address 1BRiSksEx7wioajqneij9Q6cvZFRDBUwgW

Wrong. I can change transaction and it will be valid. I can not change outputs, but I can change txid

[Perlover]

Wrong. I can change transaction and it will be valid. I can not change outputs, but I can change txid

Are you sure?
I think after these manipulations the sign for inputs from original transaction from address 18pdeFhs7mtLXMZFkbVkEfaEbp4WeW9qYm will be broken.

[amaclin]

Are you sure?

I can publish a doublespending transaction here. It will be the same: same inputs, same outputs, same fee... but another txid

Please, read the section "Signature Malleability" https://en.bitcoin.it/wiki/Transaction_Malleability

[cr1776]

Wrong. I can change transaction and it will be valid. I can not change outputs, but I can change txid

Are you sure?
I think after these manipulations the sign for inputs from original transaction from address 18pdeFhs7mtLXMZFkbVkEfaEbp4WeW9qYm will be broken.

He is sure.  Check out the link in his message.

[Perlover]

Thanks for description of the Malleability!
I will read later the Bitcoin protocol again about this.

[amaclin]

Thanks for description of the Malleability!
I will read later the Bitcoin protocol again about this.

In fact this is not bitcoin-specific.
It is a feature of ECDSA signature.
Or even a feature of arithmetic. Quadratic equation has two roots.  

[amaclin]

What happens if owner of address 1BRiSksEx7wioajqneij9Q6cvZFRDBUwgW will want to make double spending now?

No one will care. It is your problem, not the problem of other people.
There were such cases in past. No one remembers them.

I do think that the owner of 1BRiSksEx7wioajqneij9Q6cvZFRDBUwgW is dishonest man.
I do think that zero-fee is intentional for purpose of future doublespending.
for example these transactions in unconfirmed chain
https://blockchain.info/tx/dce680bcfb7002dee683261137010015f5a8db78b069afce398fb4c6e68223f9
https://blockchain.info/tx/8203679c6ef23a0daa0128a25e8582e09fd52d5455d4050939c71d3b892d810d
have 1-of-1 multisig inputs.
What is a reason to use 1-of-1? Hiding something?

[cr1776]

What happens if owner of address 1BRiSksEx7wioajqneij9Q6cvZFRDBUwgW will want to make double spending now?

No one will care. It is your problem, not the problem of other people.
There were such cases in past. No one remembers them.

I do think that the owner of 1BRiSksEx7wioajqneij9Q6cvZFRDBUwgW is dishonest man.
I do think that zero-fee is intentional for purpose of future doublespending.
for example these transactions in unconfirmed chain
https://blockchain.info/tx/dce680bcfb7002dee683261137010015f5a8db78b069afce398fb4c6e68223f9
https://blockchain.info/tx/8203679c6ef23a0daa0128a25e8582e09fd52d5455d4050939c71d3b892d810d
have 1-of-1 multisig inputs.
What is a reason to use 1-of-1? Hiding something?

I agree. Something is fishy here. 

OP should be very careful until there is a confirm. OP should let you mall the transaction for him.

[Perlover]

for example these transactions in unconfirmed chain
https://blockchain.info/tx/dce680bcfb7002dee683261137010015f5a8db78b069afce398fb4c6e68223f9
https://blockchain.info/tx/8203679c6ef23a0daa0128a25e8582e09fd52d5455d4050939c71d3b892d810d
have 1-of-1 multisig inputs.

I think there are not 1-of-1 multisig inputs

ScriptSig there is OP_FALSE <Sig> <PubKey>

But ScriptPubKey of one from some previous transactions is:

OP_HASH160 1552176c514023ac00e2a700166a86c8a1e6ec87 OP_EQUAL

As i understand it tell that output should be spent without signature, only based on hash of pubkey?
So "dishonest man" could not have a private key?