david wong

Hey! I'm David, a security consultant at Cryptography Services, the crypto team of NCC Group . This is my blog about cryptography and security and other related topics that I find interesting.

Mtgox statement and transaction malleability

posted February 2014

Mtgox, which is frozen while it is trying to fix its problems, has issued a press released explaining what is the problem

Bitcoin transactions are subject to a design issue that has been largely ignored, while known to at least a part of the Bitcoin core developers and mentioned on the BitcoinTalk forums. This defect, known as "transaction malleability" makes it possible for a third party to alter the hash of any freshly issued transaction without invalidating the signature, hence resulting in a similar transaction under a different hash. Of course only one of the two transactions can be validated. However, if the party who altered the transaction is fast enough, for example with a direct connection to different mining pools, or has even a small amount of mining power, it can easily cause the transaction hash alteration to be committed to the blockchain.

thread on bitcointalk forum

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