Removing unconfirmed transactions and unlocking the bitcoins to use again

[darkstarzz69]

Hi all,

I have google searched the topic above and have been led to many discussions that took place before which are irrelevant today.

I have been researching about 0 transaction fee payments recently and found that it doesn't get through anymore. Using an online wallet such as Blockchain.info, these bitcoins are returned after a long waiting time. (days even).

I did a test and sent multiple 0.01 btc to an address and set the transaction fee to 0. They were all stuck and after a long time became available to use again.


Is there a way to unlock these transactions sooner, rather than waiting for the funds to be unlocked? Anyone has had any good or bad experience trying this as well?

[achow101]

Hi all,

I have google searched the topic above and have been led to many discussions that took place before which are irrelevant today.

How are they irrelevant? What I am about to explain to you has been discussed over and over again, and nothing has changed since those discussions happened

I have been researching about 0 transaction fee payments recently and found that it doesn't get through anymore. Using an online wallet such as Blockchain.info, these bitcoins are returned after a long waiting time. (days even).

I did a test and sent multiple 0.01 btc to an address and set the transaction fee to 0. They were all stuck and after a long time became available to use again.


Is there a way to unlock these transactions sooner, rather than waiting for the funds to be unlocked? Anyone has had any good or bad experience trying this as well?

Technically they are not locked. There is nothing in the protocol that prevents you from sending another transaction that spends the same input, it is just that wallets do not allow this to prevent double spend attempts. To spend the Bitcoin, you need your wallet to forget about the unconfirmed transactions. This can be done many ways and the methods differ for each client. IIRC blockchain.info doesn't allow this. Since the transactions have 0 fee, you are more likely to be able to double spend since nodes will not have relayed the transaction.

There are methods to increase the fee of a transaction. If an output went back to you in the transaction, you can attempt a CPFP (Child pays for parent) transaction where you spend that output and pay the fee for both the unconfirmed transaction and the new transaction in the new transaction's fee. The other method is a RBF (Replace by fee) transaction which allows you to legitimately double spend the transaction. RBF allows new transactions that spend the same inputs of an unconfirmed transaction if the fee on that new transaction is higher. Both of these methods require that nodes and miners have software the support those features.

RBF will be included in Bitcoin Core 0.12 but CPFP is currently not supported by many nodes or miners. AFAIK eligius is the only pool that supports mining CPFP transactions.

[darkstarzz69]

Thanks for your reply. I thought they were irrelevant as the posts were old and discussed Bitcoin Qt 0.8 hence. I must have missed newer posts that discussed this so apologies on my part.

On a side note, relating to blockchain.info, would there be a possibility to take the wallet offline and remove those transactions, unlocking the coins. From what I understand, the 0 fee transaction doesn't reach the nodes and hence it is actually not spent however the transaction would still exist in the wallet.

I haven't had any experience taking wallets offline as I'm trying to learn much about the network but still would love to dabble with it.

Once again, apologies for my ignorance.

EDIT: Thanks for telling me about CPFP and RBF. Will be researching about those too.

[achow101]

On a side note, relating to blockchain.info, would there be a possibility to take the wallet offline and remove those transactions, unlocking the coins. From what I understand, the 0 fee transaction doesn't reach the nodes and hence it is actually not spent however the transaction would still exist in the wallet.

I haven't had any experience taking wallets offline as I'm trying to learn much about the network but still would love to dabble with it.

You could do that. It us unlikely that many boxes will know if the transaction but it is still possible. Even so, you can simply tell the wallet to forget those unconfirmed transactions so that you can spend the inputs again.

[darkstarzz69]

Thanks for your reply.

Based on the process discussed in previous discussions, would it be:

Import Private Key to Bitcoin Qt --> Export to PyWallet --> Delete Transactions --> Re-import to new wallet on Blockchain.info?

[shorena]

Thanks for your reply.

Based on the process discussed in previous discussions, would it be:

Import Private Key to Bitcoin Qt --> Export to PyWallet --> Delete Transactions --> Re-import to new wallet on Blockchain.info?

No, blockchain.info is a service, what you do locally will not change their perception of the blockchain.

You can however:

#1 export from bc.i
#2 import to core
#3 create competing TX
#4 ? ? ?

Since the topic comes up. The receiver can defened against a double spend by rebroadcasting the original transaction, lets call it A and your double spend B. Any network node that knows about A will not accept and not relay B. The receiver can also attempt to create a follow up transaction C with a higher fee in the hopes that a CPFP miner will pick them (A & C) up.

[darkstarzz69]

Hi Shorena,

Thanks for the reply. So even if I were to make changes offline and re-import to a new wallet online, the changes would not be synced?

[teonoaro]

If those coins are not needed for you immediately, or you those transactions are for just testing purpose, then leave it as is. It will be confirmed when pools don't get paid transactions. However, if you want to make it spendable immediately then you need to go with the RBF concept of double spending. Or use CPFP method to send the transaction with a fee. My guess you just leave it as it is. It will be confirmed later without a double spend issue.

[shorena]

Hi Shorena,

Thanks for the reply. So even if I were to make changes offline and re-import to a new wallet online, the changes would not be synced?

You cant do the change offline. The transaction is known to several thousand nodes in the network. You can take your private key to an offline machine, but that does not change the transactions know to the nodes online.

If those coins are not needed for you immediately, or you those transactions are for just testing purpose, then leave it as is. It will be confirmed when pools don't get paid transactions. However, if you want to make it spendable immediately then you need to go with the RBF concept of double spending. Or use CPFP method to send the transaction with a fee. My guess you just leave it as it is. It will be confirmed later without a double spend issue.

RBF (replace by fee) is not implemented yet. No node that knows about the frist TX (A) will relay the second (B) competing TX. Even if RBF would already be implemented, the TX A would have to be made in a specific way before broadcasting to allow RBF at all.