藍色小惡魔 - 舒活札記

我想這就是目前在下班時間開始瘋狂崩盤的主因了，MtGox 說這個問題不是他們自己的，而是整個 Bitcoin 的嚴重問題！？

因為太聳動了～先用 Google 翻譯成中文如下 >"<~ 淚奔...

湊合著看吧！ 

親愛的MtGox客戶和比特幣使用者， 如你所知，在MtGox團隊一直在努力與比特幣提款的處理方式解決某個問題。

通過“比特幣提款”我們指的是比特幣錢包從MtGox交易到外部比特幣地址。比特幣交易的任何MtGox比特幣地址，取款貨幣（日元，歐元等）不會受到這個問題。

我們已經確定的問題並不僅限於MtGox，並影響地方比特幣被發送到第三方的所有交易。我們認為，需要解決這一問題的變化將在長期內對整個社會正面的。因此我們採取了暫停比特幣提款的必要行動，直到這一技術問題已得到解決。

解決交易展性 MtGox 已檢測到異常活動，其比特幣錢包，在過去幾個星期進行調查。這證實它需要更密切地審查交易的存在。

非技術性解釋：在比特幣軟件中的bug使得它可能是有人使用比特幣網絡改變交易細節，使它看起來像一個發送比特幣的一而事實上，它確實發生了比特幣錢包並沒有出現。由於交易，若沒有正確進行顯示，在比特幣可能被重新發送。

MtGox正在與比特幣核心開發團隊和其他人，以減輕這個問題。

技術說明：比特幣交易須待設計問題已經在很大程度上被忽略，而已知的比特幣核心開發人員至少一部分並在 BitcoinTalk 提到論壇。此缺陷，被稱為“交易可塑性”可讓第三方來改變任何新鮮事務發出的散列不使簽名無效，從而導致下一個不同的散列類似的交易。當然，只有兩筆交易中的一個可以被驗證。但是，如果誰改變了交易的一方是速度不夠快，例如直接連接到不同的採礦池，或者即使有少量開採的權力，它可以很容易導致交易哈希改動提交到 blockchain 的Bitcoin的API“sendtoaddress”廣泛用於發送比特幣給定的比特幣地址將返回一個事務哈希作為一種方法來跟踪事務的插入在blockchain。

大多數的錢包和交換服務將保持這個記錄表示哈希為了能夠向用戶作出回應，他們應該詢問他們的交易。它很可能是這些服務將假定，如果它沒有出現在與原始哈希blockchain和具有目前沒有方法可以識別為他們的替代交易的有效方法的交易，不發送。

這意味著，一個人可以請求來自交易所或錢包服務比特幣，改變納入blockchain之前所產生的交易的哈希值，然後與發證服務，同時聲稱該交易沒有繼續進行。如果修改失敗，用戶可以簡單的發送比特幣返回重試，直到成功為止。

我們相信，這可以通過使用不同的散列事務跟踪目的加以解決。而網絡將繼續使用當前的哈希值包含在每個塊的梅克爾樹的目的，新的哈希值的目的是要跟踪一個給定的事務，並可以計算和編制索引通過散列通過SHA256確切的簽署字符串（在同一交易方式目前散列）。

這種新的交易哈希將允許簽約各方保持雙方已簽署並可以很容易地計算出，甚至對過往交易的任何交易的軌道。

我們已經討論了這個解決方案的比特幣核心開發人員，並允許比特幣提款再次它已被批准並標準化。

在此期間，交流和錢包服務-和任何服務直接傳送硬幣給第三方-應該非常小心，任何人都聲稱他們的交易並沒有通過。 請注意，這也將影響其他任何加密使用的貨幣相同的交易計劃，作為比特幣。結論 要正確地看待事物，重要的是要記住，比特幣是一個非常新的技術，還是很早期階段。什麼MtGox和Bitcoin的社會已經經歷了過去一年一直是一個令人難以置信的和令人興奮的挑戰，還有很多工作要做，以進一步改善。

MtGox將恢復比特幣提款以外的錢包，一旦上述問題已經得到妥善的解決方式，將更好地服務於廣大客戶。 對這一問題的狀態的更多信息將盡快公佈。 我們感謝您抽出寶貴的時間來閱讀這一點，尤其是對你的耐心。

最好的問候 MtGox團隊 

Dear MtGox Customers and Bitcoiners,

As you are aware, the MtGox team has been working hard to address an issue with the way that bitcoin withdrawals are processed. By "bitcoin withdrawal" we are referring to transactions from a MtGox bitcoin wallet to an external bitcoin address. Bitcoin transactions to any MtGox bitcoin address, and currency withdrawals (Yen, Euro, etc) are not affected by this issue.

The problem we have identified is not limited to MtGox, and affects all transactions where Bitcoins are being sent to a third party. We believe that the changes required for addressing this issue will be positive over the long term for the whole community. As a result we took the necessary action of suspending bitcoin withdrawals until this technical issue has been resolved.


Addressing Transaction Malleability
MtGox has detected unusual activity on its Bitcoin wallets and performed investigations during the past weeks. This confirmed the presence of transactions which need to be examined more closely. 


Non-technical Explanation: 
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.


Technical Explanation:
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.

The bitcoin api "sendtoaddress" broadly used to send bitcoins to a given bitcoin address will return a transaction hash as a way to track the transaction's insertion in the blockchain.
Most wallet and exchange services will keep a record of this said hash in order to be able to respond to users should they inquire about their transaction. It is likely that these services will assume the transaction was not sent if it doesn't appear in the blockchain with the original hash and have currently no means to recognize the alternative transactions as theirs in an efficient way.

This means that an individual could request bitcoins from an exchange or wallet service, alter the resulting transaction's hash before inclusion in the blockchain, then contact the issuing service while claiming the transaction did not proceed. If the alteration fails, the user can simply send the bitcoins back and try again until successful.

We believe this can be addressed by using a different hash for transaction tracking purposes. While the network will continue to use the current hash for the purpose of inclusion in each block's Merkle Tree, the new hash's purpose will be to track a given transaction and can be computed and indexed by hashing the exact signed string via SHA256 (in the same way transactions are currently hashed).

This new transaction hash will allow signing parties to keep track of any transaction they have signed and can easily be computed, even for past transactions.

We have discussed this solution with the Bitcoin core developers and will allow Bitcoin withdrawals again once it has been approved and standardized. 

In the meantime, exchanges and wallet services - and any service sending coins directly to third parties - should be extremely careful with anyone claiming their transaction did not go through.

Note that this will also affect any other crypto-currency using the same transaction scheme as Bitcoin.


Conclusion
To put things in perspective, it's important to remember that Bitcoin is a very new technology and still very much in its early stages. What MtGox and the Bitcoin community have experienced in the past year has been an incredible and exciting challenge, and there is still much to do to further improve. 

MtGox will resume bitcoin withdrawals to outside wallets once the issue outlined above has been properly addressed in a manner that will best serve our customers.

More information on the status of this issue will be released as soon as possible. 

We thank you for taking the time to read this, and especially for your patience.

Best Regards,
MtGox Team

https://www.mtgox.com/press_release_20140210.html