This had the effect of throwing a spotlight bitcoin the attack vector for DoS bad actors. Gox transaction so malleability of its customers bugs remains unclear, but it could — bitcoin least theoretically — be true. There are 20 comments. Bugs — a hash function is an algorithm that maps data of arbitrary malleability to data of a fixed length. These aren't, and bitcoin is not broken. The spin that transaction malleability caused all client funds to be stolen from the Silk Road mainframe is so thin that no-one even bothers to debate transaction Not handling malleability in your software, that is a bug or as some would call it:
Remember that the transaction itself has not changed. Gox Fiasco Bitcoin blogger Arianna Simpson explains "all this hot wallet cold storage transaction malleability business" in layman's terms. Submit link NOT about price. If that happens, the network will assume that transaction is valid, and won't record Alice's. Once a transaction is added to the blockchain, the transaction, including the signature becomes immutable. Okay makes sense its also all over the New York Times today
So until that happens, it's not hard bugs deal with this properly. Bitcoin core developer Gregory Maxwell muses about malleability possibility here. MtGox, screwed by their own faulty implementation and suckered into giving away bitcoin again by transaction claiming their tx didn't go through. That same optimism most definitely does not apply to Mt. That wasn't the bitcoin core developers' fault, but transaction they failed to do was to get malleability bitcoin client to double-check that the signature was properly formed before bugs handed it over. Order bitcoin newest oldest recommendations.
Bitcoin uses public and private key pairs to secure bitcoin transactions and digitally sign them. Transaction inputs contain information about previous transactions involving the same bitcoins currently being spent.
Since it is not logically possible for a signature to sign itself chickens and eggs! Whilst the transaction as a whole, or in part, cannot be changed without breaking validity in relation to the signature, the signature can be changed.
So, given a transaction and its accompanying valid digital signature, it is possible for someone to generate an equivalent signature, but with the caveat that the transaction id hash will also change in response.
Remember that the transaction itself has not changed. In fact, a change to any aspect of the transaction other than the input. Since nothing about the transaction inputs or outputs amount, timestamp, target address has changed, our malleated transaction may be included in a block by a miner, thereby being confirmed, and the receiving party will get paid.
The equally valid original transaction will in this case be picked up as an attempt to double spend and the network will reject it. If a custom wallet were to, say, use transaction id as a primary identifier when looking to the network for transaction confirmation, then malleation would compromise its ability to do so.
Miners have no preference or ability to distinguish between an original transaction and its malleated version, so it is a matter of fate as to which one gets mined first and thus confirmed on the network. Confirmation is made by transaction id: Right from Gox site where I log in from: A bug in the bitcoin software makes it possible for someone to use the Bitcoin network to alter transaction details to make it seem like a sending of bitcoins to a bitcoin wallet did not occur when in fact it did occur.
Since the transaction appears as if it has not proceeded correctly, the bitcoins may be resent. MtGox is working with the Bitcoin core development team and others to mitigate this issue. Okay makes sense its also all over the New York Times today I'm not sure if this needs to be tracked here for when the change becomes available as reminder.
I will let somebody decide to close this bug or not. Thanks for your attention and quick advice. On Mon, Feb 10, at From where I'm sitting the mtgox press release is making it sound far worse than it actually is. Reply to this email directly or view it on GitHubhttps: This is not a bug in Bitcoin, you can read an official statement from the Bitcoin Foundation https: If the Bitcoin team implement changes to reduce transaction malleability upstream, then we will consider integrating them.
In the end it did not allow any double spends or any bad transactions to ever be accepted bad in that funds from the correct inputs were properly sent to the correct outputs. What it could do was 'spoof' some people's accounting software. The level of incompetence and now, outright fraud, demonstrated by MtGox is profound and I too feel that them leaving the picture to be replaced by more professional operations is a good thing.
Watching the price quickly recover is an indication that I'm not the only person who thinks that. Ok, ok, I've ready everyone's 'explanations' and I guess we are down to semantics here. In my personal view, the fact that all parts of the transaction generated by the sender are not signed is a bug.
That's just how I view it, and you won't easily convince me otherwise. So, let's discuss all of the portions of the transaction which are signed. If you created a transaction hash from those parts, it would be immutable, correct?
I agree that the hash or a new transaction ID field should be formed only from parts of the transaction that are signed. The issue must be what you define as a bug. If the spec said one thing and bitcoin worked differently, that would be a bug, imho. But bitcoin itself is working exactly as designed and as specified. Sure, tx malleability might be an undesirable or unwanted attribute in some people's opinions, but calling it a bug is misleading and implies that something is not working as expected.
It is clearly a bug if a 3rd party can submit a modified version of someone else's transaction and have it accepted by the blockchain.
That is exactly valid behavior since the system then does exactly what it's designed to do: It has always been clear that you look for the system to validate the tx, and cannot use the tx id.
And it doesn't give any free money to anyone who ignores that rule, so the only person hurt by ignoring the rule is the person who did it. MtGox, screwed by their own faulty implementation and suckered into giving away bitcoin again by people claiming their tx didn't go through. If I told you my toilet can't flush paper towels and you try it anyway and it doesn't flush, who's fault is that? You might be misunderstanding.
The system does not reject the 3rd party modified transaction, it accepts it as being valid, even though it is not. The only valid transaction is the one originally signed by the sender. In the case of a modified transaction the original sender's transaction gets rejected as a double spend.
If you think it is valid and correct behavior for a 3rd party hacker to be able to modify your transaction and have it accepted by the network, I'm quite surprised by that. Just because they have not figured out a way yet to modify it in a way that steals money, does not make it particularly acceptable.
Indeed, you are correct that the second transaction can be the one accepted. I was in error. But it will always necessarily be identical to the first transaction, otherwise it would not be accepted. When you say a 3rd party hacker can modify my transaction, this isn't accurate. Nothing about the transaction itself not the amount, nor the recipient can be modified, only the "wrapper", in a sense. It's the same candy bar inside. It's like sending the same letter in a different envelope, verifiably signed by the same person and with the same letterhead, date, and fancy paper as the original.
Who cares what envelope it came in? It matters not at all to the recipient. When they see the first one delivered in the next mail they realize that it's a duplicate, scratch their head, and move on with life. People seem to want Bitcoin to be as easy as a credit card. Those people will always be sorely disappointed. I meant "easy" as in "I just want to swipe my Bitcoin card and not have to think about it". Using Bitcoin takes more thought than using Visa.
As a rule, many people hate thinking. Because of the nature of transactions on the Bitcoin network, six confirmations on the blockchain before spending an input has always been recommended. You can't even spend a mined coin until confirmations have passed. It's not a bug because a bug would imply that bitcoin is imperfect and that kind of thinking is not allowed around here.
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Welcome to Reddit, the front page of the internet. Become a Redditor and subscribe to one of thousands of communities. This is an archived post. You won't be able to vote or comment. Bitcoin submitted 3 years ago by jratcliff And, explain to me like I'm 52, why that isn't a bug? Want to add to the discussion? Not signing everything in the transaction is a bug.
It doesn't break software that is designed properly. And the proposal to fix it, including corresponding protocol change, has already been made available here: With output script I'm referring to scriptPubKey. Shady as fuck, just like everything else in the bitcoin community.
Fix the protocol and make everyone upgrade! That said, two significant mitigating factors exist: This is the important part that the naysayers want to ignore. This is good for bitcoin? Under no circumstances would that or should that be considered valid behavior.
29 Nov While transactions are signed, the signature does not currently cover all the data in a transaction that is hashed to create the transaction hash. Thus, while uncommon, it is possible for a node on the network to change a transaction you send in such a way that the hash is invalidated. Note that this just. 16 Aug Transaction Malleability Explained. One of the benefits of SegWit, scheduled to activate on the network very soon, is that it fixes something called transaction malleability. In this article, I'm going to explain what malleability is and why fixing it is important. 16 Feb The score here is zero because the wallet is implemented with transaction malleability in mind and the bug being fixed for the upcoming release is merely a display bug. Due to the complexity of the Bitcoin protocol's encryption and signature model, the developers only expect to eliminate this issue after a.