Blockhain.info TX Problem?

[buffett]

i have two strange transaction going on

one got this email from blockchain:

https://blockchain.info/tx/2138dfd81464aeec181b431e916d83df83e90776fc13cc69ff15535003fdf440

Transaction Confirmation Failed

A transaction made through Blockchain.info has been removed from our database because it was taking a long time to be included in a block.

Any funds have been returned to your wallet and you can now spend the coins again. Please consider including a larger fee in future transactions.

it seems the txid is changing to: https://blockchain.info/tx/ed5d19731b6cbfd43494715a2f21538dc191671e076eda750d08ab1e2bcf7125

the other tx is https://blockchain.info/tx/c23f56efa4a0c111cf1470b8134041d981f66eddcd6ccfb66e9c617aa6efc0be, which has this notice at the top of blockchain page:  Warning! this transaction is a double spend of 112591137. You should be extremely careful when trusting any transactions to/from this sender.

the tx become https://blockchain.info/tx/965897806a8b772ef5e961ebf8c14c6ca43599e6482395b8a05e7c8797dbf9c3

all transactions are sent with blockchain API.

what's wrong with blockchain, and should i be worried? is it related to transaction malleable?

[jl2012]

Quick answer: don't need to worry. You fund is perfectly safe

[jl2012]

Someone is using the malleability to spread FUD. It looks bad but won't lead to any real harm.

[buffett]

Quick answer: don't need to worry. You fund is perfectly safe

what's going on with blockchain? is the whole network effected by malleable attack?

[jl2012]

Quick answer: don't need to worry. You fund is perfectly safe

what's going on with blockchain? is the whole network effected by malleable attack?

Blockchain.info mistakenly thinks those transactions are double-spending but actually they are not. However, these are all cosmetic issue and no real harm could be done.

I have pm-ed piuk asking him to stop reporting double-spending on his service for now

[buffett]

Quick answer: don't need to worry. You fund is perfectly safe

what's going on with blockchain? is the whole network effected by malleable attack?

Blockchain.info mistakenly thinks those transactions are double-spending but actually they are not. However, these are all cosmetic issue and no real harm could be done.

I have pm-ed piuk asking him to stop reporting double-spending on his service for now

everytime i send btc to my customer, i also send email notification of the txid. so now this practice should be avoided because huge chance that txid can be altered? and should we store the txid into our database? if not, how we determine each transaction from our end?

what should we do as merchant/developer to anticipate this malleability issue?

[jl2012]

everytime i send btc to my customer, i also send notification of the txid. so now this practice should be avoided because huge chance that txid can be altered? and we should not store the txid into our database?

what should we do as merchant/developer to anticipate this malleability issue?

You can still rely on txid, but ONLY AFTER SEVERAL CONFIRMATIONS

Confirmation is the king: not just for the safety of the fund, but also for the reliability of txid

[jl2012]

For merchants, if they want to record a transaction immediately without waiting for confirmation, what they could do now is to record the inputs (txid:index), outputs (address), and values. These information, altogether, is not malleable and could be an unique identifier for a transaction, even for zero confirmation

[renee25]

so bitcoin 102 guy and gox maybe right after all 

[buffett]

For merchants, if they want to record a transaction immediately without waiting for confirmation, what they could do now is to record the inputs (txid:index), outputs (address), and values. These information, altogether, is not malleable and could be an unique identifier for a transaction, even for zero confirmation

what is txid:index?

[nmersulypnem]

everytime i send btc to my customer, i also send notification of the txid. so now this practice should be avoided because huge chance that txid can be altered? and we should not store the txid into our database?

what should we do as merchant/developer to anticipate this malleability issue?

You can still rely on txid, but ONLY AFTER SEVERAL CONFIRMATIONS

Confirmation is the king: not just for the safety of the fund, but also for the reliability of txid

Wait - I thought that this wasn't true.  I thought that the altered transaction might be accepted to the block chain before the original one does, and so you can have a situation where the service thinks it didn't go through, but in fact the attacker DID get the BTC.  If the attacker does that multiple times, they could withdraw an unbounded amount from the service.

[dserrano5]

what is txid:index?

Inputs to transactions refer to previously confirmed transactions and an index within, ie "The second output in transaction 01234567". This is what "txid:index" refers to.

[buffett]

what is txid:index?

Inputs to transactions refer to previously confirmed transactions and an index within, ie "The second output in transaction 01234567". This is what "txid:index" refers to.

still don't get it. how to get txid:index from bitcoind?

[dserrano5]

what is txid:index?

Inputs to transactions refer to previously confirmed transactions and an index within, ie "The second output in transaction 01234567". This is what "txid:index" refers to.

still don't get it. how to get txid:index from bitcoind?

With 'bitcoind listunspent'.

Example output:

Code:

[
    {
        "txid" : "3bec01c0bf0f52f79043abfbe3ba2c21ae417ffea74bf152368418df21a1d939"
        "vout" : 1,
        […]
    },
    {
        "txid" : "9125d985a969a4c0a9cd7686a2d7e96cff886e55697ddc809639b3e690c558b8",
        "vout" : 0,
        […]
    },
    […]
]

The first entry refers to the second output in tx 3bec01c0bf0f52f79043abfbe3ba2c21ae417ffea74bf152368418df21a1d939 (59.3 BTC), the second entry refers to the first output in tx 9125d985a969a4c0a9cd7686a2d7e96cff886e55697ddc809639b3e690c558b8 (0.5 BTC) and so on. Try it with your wallet, you should be able to check in blockchain.info that all entries in your list appear as unspent, which they really are (unlike this example, where I just picked a couple of random txs).

The sum of amounts in all your unspent outputs is your balance. That's how bitcoind figures it out.