What the hell is wrong with this transaction...

[tarashy]

Hey there,

for our shop we use the Blockchain API to generate (artificial) addresses for each customer (https://blockchain.info/de/api/api_receive). The customer himself sends then bitcoins to that generated address and finaly bitcoins are forwarded to our address.

One of our customers send his money to an generated address, this transaction already has 56 confirmations, but the the final forwading to our address gets no confirmations at all.

May you have a look and tell me whats wrong?

This is the address that should forward:
https://blockchain.info/address/19M6gi58egd8HTxpR6AmE7CYo5Eyq9aX9P

[tarashy]

Am I right, that this is the beginning transaction thats blocks all the other transactions up to mine???

https://blockchain.info/tx/6024d009d6bb318bd8edb74957ad5d32aba8ca856c42ba6197ea138a7019a24a

[twister]

One of the sending address: 1CLLMQTGCtRTHvmDiJcXNbZry5n63tfsiQ
has an unconfirmed received transaction: dc776f9b788352dff862c6000a07ab6b202fae899b1cf457c0e65a84b076844f
when it goes through, the other will go through as well.

[tarashy]

Yes, I realized. But this transaction also has a non confirmed transaction and so on and so on and so on...up to the transaction I replied a second ago. How long may it take in worst case??

thanks

[twister]

Yes, I realized. But this transaction also has a non confirmed transaction and so on and so on and so on...up to the transaction I replied a second ago. How long may it take in worst case??

thanks

Yes, I see that now but considering all were sent with a Tx fee, they'll all get through soon. Not too sure but it may take up to an hour.

Although, I see now, this one is the culprit because the Tx fee used in this one is just 1k satoshi:

Am I right, that this is the beginning transaction thats blocks all the other transactions up to mine???

https://blockchain.info/tx/6024d009d6bb318bd8edb74957ad5d32aba8ca856c42ba6197ea138a7019a24a

[tarashy]

Hm, to be honest... I doubt. The transaction concerned was initially started 2014-12-05 21:02:42 .......thats more then 15h now.

[twister]

Yeah, you're right, it might take more because the initial transaction you posted above has a low miner's fee.

[shorena]

Hm, to be honest... I doubt. The transaction concerned was initially started 2014-12-05 21:02:42 .......thats more then 15h now.

As you allready know this all depends on the TX [1] which is 2207 bytes in size but only pays 1000 Satoshi in fees. 20000 Satoshi would be reasonable. This will take a while.


[1] https://blockchain.info/de/tx/6024d009d6bb318bd8edb74957ad5d32aba8ca856c42ba6197ea138a7019a24a

[tarashy]

Oh damn. Because  the transaction consists of 12 parts, I expect a lenghts of 24 hours (by experiance)?!

By the way: Nice chain exploit if would create thousands of those transactions at the same time...  isnt it?

[shorena]

Oh damn. Because  the transaction consists of 12 parts, I expect a lenghts of 24 hours (by experiance)?!

While the size in bytes matters, the age and size of the inputs also matters.
See the formular for priority [1].

By the way: Nice chain exploit if would create thousands of those transactions at the same time...  isnt it?

I wouldnt call it an exploit. As long as someone along the chain does not accept zero confirmation transactions the "attack" fails. And you should not accept transactions without confirmations for several reasons anyway.


[1] https://en.bitcoin.it/wiki/Transaction_fees#Technical_info

[tarashy]

And you should not accept transactions without confirmations for several reasons anyway.

As far as I know, I cant choose when using Blockchain's API.....

[cr1776]

And you should not accept transactions without confirmations for several reasons anyway.

As far as I know, I cant choose when using Blockchain's API.....

That would be something to discuss with blockchain.info then, use someone else's API, or run your own Bitcoin core. If you can't choose that when using the bc.i API this is the type of situation they should help protect against.

This seems off-topic for this section by the way.

[yakuza699]

I wouldnt call it an exploit. As long as someone along the chain does not accept zero confirmation transactions the "attack" fails. And you should not accept transactions without confirmations for several reasons anyway.

It is really hard for an attacker to send a big chain of transactions spending each other and using 0 as a fee as most of the bitcoin nodes will simply not relay those transactions as there are many anti-ddos mechanisms on bitcoin core clients.

To op. Does your shop accepts 0 confirmation transactions?