民間辦學是罪?|全民教育局HKEd4All

劉山青

76年港大理科生,民運人士,曾在國內因支持民主而坐牢十載。退休後的生活,花1分鐘就可以說完,並非懶人包:每周有半天與老友打乒乓球,半天玩滑浪風帆。其他時間到友人的辦公室上網寫網誌,周而復始,假期與我無關。

比特幣是什麼?|劉山青網誌

2017-8-12 14:38
字體: A A A

中國央行正加強控制網上的非銀行業務(註一)的交易,推出以公司形式成立一網上平臺,並強制所有網上支付需要在明年8月前加入(註四)。

旅美經濟學者何清漣表示:「這是清理影子銀行系統的舉措,目標在全國那近30家由國企及民企資本大鱷控制的金融平臺,這些金融平臺幾乎拿到了整套金融業務全牌照,業務流量太大,出了不少問題。這不是針對普通消費者的措施,應該影響不是很大。」

中國人民银行有專題討論,表示:「與集中支付體系相比……比特幣,交易時只改變帳戶數量資訊,沒有發生實質上的區塊鏈交易移動,因此不管哪類交易情況下部分網路癱瘓也不影響整個系統運行,在資料傳遞和記帳登記上穩定性高於雙中心的架構。(註三)」美國財政部認為,比特幣被用作支持恐怖主義和洗黑錢(註五)。

比特幣由中本聰先生在2008年的一篇只有九頁的論文建立理論基礎,並在2009年建立比特幣網絡。他的文章雖然有中譯本。但直譯法仍然不能避免過於技術性,不利一般性認識。本文嘗試以筆者理解後,再添加其他來源知識,希望讀者對比特幣有一個初步認識。應該注意,當中的中文並非嚴格翻譯,必然有錯漏。

Abstract.

A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as a majority of CPU power is controlled by nodes that are not cooperating to attack the network, they’ll generate the longest chain and outpace attackers. The network itself requires minimal structure. Messages are broadcast on a best effort basis, and nodes can leave and rejoin the network at will, accepting the longest proof-of-work chain as proof of what happened while they were gone.

摘要

點對點的電子現金讓人們直接進行支付活動而無須經過金融機構。電子簽名方式可解決同一筆錢被多重支付的問題,但其缺點是仍然要經過第三方作保證。比特幣方案解決了這限制。

比特幣運用時間戳記(timestamp)、雜湊(hash)和「基於雜湊的工作量證明」(hash-based-proof-work)組成的一條鏈(chain)。這條鍵紀錄了之前的所有交易,偽造者要重頭組成同樣長度的鏈,付出同樣多的電腦資源,因而並不化算。

這條鍵被由掘金者以「基於雜湊的工作量證明」方法制成,由閒散在各地的義務個人電腦(也稱之為節點,nodes)保存。目前全球在每一時段約有一萬至7千個自由參與的節點。最長的鍵就是最有公信用的鍵。基本上,每一個節點在驗證比特幣交易的真偽上是每一電腦一票的。節點可自由聯網或離開。

1. Introduction

Commerce on the Internet has come to rely almost exclusively on financial institutions serving as trusted third parties to process electronic payments. While the system works well enough for most transactions, it still suffers from the inherent weaknesses of the trust based model. Completely non-reversible transactions are not really possible, since financial institutions cannot avoid mediating disputes. The cost of mediation increases transaction costs, limiting the minimum practical transaction size and cutting off the possibility for small casual transactions, and there is a broader cost in the loss of ability to make non-reversible payments for nonreversible services. With the possibility of reversal, the need for trust spreads. Merchants must be wary of their customers, hassling them for more information than they would otherwise need. A certain percentage of fraud is accepted as unavoidable. These costs and payment uncertainties can be avoided in person by using physical currency, but no mechanism exists to make payments over a communications channel without a trusted party. What is needed is an electronic payment system based on cryptographic proof instead of trust, allowing any two willing parties to transact directly with each other without the need for a trusted third party. Transactions that are computationally impractical to reverse would protect sellers from fraud, and routine escrow mechanisms could easily be implemented to protect buyers. In this paper, we propose a solution to the double-spending problem using a peer-to-peer distributed timestamp server to generate computational proof of the chronological order of transactions. The system is secure as long as honest nodes collectively control more CPU power than any cooperating group of attacker nodes.

引言

現行電子支付(如支付寶等)需要第三方作中介。雖然它普遍被使用,但它仍然存有信託制度的既有問題,例如第三方的作弊問題。中介費用高增加了交易成本,限制了小額交易的可能性。交易商有可能索取不必要的個人資料。現鈔交易可以免除上述毛病,但電子支付仍然解決不了。本文提出的數學方法令交易紀錄無法偽造,因此可給交易雙方信心。在這裡,只要有足夠的義務節點,偽幣不會存在。

2. Transactions

We define an electronic coin as a chain of digital signatures. Each owner transfers the coin to the next by digitally signing a hash of the previous transaction and the public key of the next owner and adding these to the end of the coin. A payee can verify the signatures to verify the chain of ownership. The problem of course is the payee can’t verify that one of the owners did not double-spend the coin. A common solution is to introduce a trusted central authority, or mint, that checks every transaction for double spending. After each transaction, the coin must be returned to the mint to issue a new coin, and only coins issued directly from the mint are trusted not to be double-spent. The problem with this solution is that the fate of the entire money system depends on the company running the mint, with every transaction having to go through them, just like a bank. We need a way for the payee to know that the previous owners did not sign any earlier transactions. For our purposes, the earliest transaction is the one that counts, so we don’t care about later attempts to double-spend. The only way to confirm the absence of a transaction is to be aware of all transactions. In the mint based model, the mint was aware of all transactions and decided which arrived first. To accomplish this without a trusted party, transactions must be publicly announced [1], and we need a system for participants to agree on a single history of the order in which they were received. The payee needs proof that at the time of each transaction, the majority of nodes agreed it was the first received.

比特幣交易

電子貨幣是一連串的電子簽署。電子貨幣持有人在支付時,首先電子確認,再將其確認加密在這批電子貨幣上。收款人會得到一條公眾鑰匙,作一定數量的電子貨幣的持有人身份。收款人可在過往紀錄上查冊。問題是,收款人如何保證這批電子貨幣在同一時間沒有被支付多次呢?以第三方(鑄幣廠模式)的解決方法是,金融機構先從支付者收回這批電子貨幣,然後發行新的電子貨幣給收款人。

這方法的缺點是過份依賴第三方,讓它擁有央行的權力。我們需要找出一個方法,讓收款人在不需要第三方的情況下,確知貨幣沒有被重複支付。在我們的方法裡,只需要確保第一次支付沒有被濫用就可以了。我們要知道所有的交易紀錄。第三方模式知道所有交易,因此它知道早來遲來的交易。

我們的方法是不經第三方的,所以我們需要將所有交易公開透明,參與者需要認同一條交易時間序列(區塊鍵)。若作為公證的節點以大比數確認了最長的區塊鍵時,收款人就可以以此來保證交易成功,他沒有收到偽幣。

3. Timestamp Server

The solution we propose begins with a timestamp server. A timestamp server works by taking a hash of a block of items to be timestamped and widely publishing the hash, such as in a newspaper or Usenet post [2-5]. The timestamp proves that the data must have existed at the time, obviously, in order to get into the hash. Each timestamp includes the previous timestamp in its hash, forming a chain, with each additional timestamp reinforcing the ones before it

時間戳伺服器

中本聰在2008年建議設立一個時間戳伺服器。它為每一個區聯塊打上時間戳,以證明該區聯塊何時產生。每一時間戳包括其之前的時間戳,連成一條鍵。現在,掘金者取代了時間戳伺服器功能,為區聯塊打上時間戳。

4. Proof-of-Work

To implement a distributed timestamp server on a peer-to-peer basis, we will need to use a proof -of- work system similar to Adam Back’s Hashcash [6], rather than newspaper or Usenet posts. The proof-of-work involves scanning for a value that when hashed, such as with SHA-256, the hash begins with a number of zero bits. The average work required is exponential in the number of zero bits required and can be verified by executing a single hash. For our timestamp network, we implement the proof-of-work by incrementing a nonce in the block until a value is found that gives the block’s hash the required zero bits. Once the CPU effort has been expended to make it satisfy the proof-of-work, the block cannot be changed without redoing the work. As later blocks are chained after it, the work to change the block would include redoing all the blocks after it. The proof-of-work also solves the problem of determining representation in majority decision making. If the majority were based on one-IP-address-one-vote, it could be subverted by anyone able to allocate many IPs. Proof-of-work is essentially one-CPU-one-vote. The majority decision is represented by the longest chain, which has the greatest proof-of-work effort invested in it. If a majority of CPU power is controlled by honest nodes, the honest chain will grow the fastest and outpace any competing chains. To modify a past block, an attacker would have to redo the proof-of-work of the block and all blocks after it and then catch up with and surpass the work of the honest nodes. We will show later that the probability of a slower attacker catching up diminishes exponentially as subsequent blocks are added. To compensate for increasing hardware speed and varying interest in running nodes over time, the proof-of-work difficulty is determined by a moving average targeting an average number of blocks per hour. If they’re generated too fast, the difficulty increases..

工作量證明

點對點的分佈式時間戳伺服器運用了『工作量證明』技巧。『工作量證明』以數學方式( hash ) 將交易紀錄制作成一串256位的數字。它以一堆零作開始。這串256位的數字的開始零越多,則需要電腦資源越多。時間戳伺服器需要一條加密鑰匙推算出一條足夠難度的256位數字(即足夠零起始的數字系列)。這是電腦資源的比併。若想改動一個區塊,其之前的工作必需重新運算。隨著區塊越堆越多,作弊越來越難。現在的『工作量證明』主要由交易商或集團式掘金者完成。他們將全球每約十分鐘的交易(約數千條)的交易加密成一個區塊,放在鍵的最頂項。全球的節點義工紀錄了這條最長的鍵,並見證成為可信的比特幣交易。累積起來的龐大的已付出的電腦資源令偽幣鑄造者無利可圖。

5. Network

The steps to run the network are as follows:
1) New transactions are broadcast to all nodes.
2) Each node collects new transactions into a block.
3) Each node works on finding a difficult proof-of-work for its block.
4) When a node finds a proof-of-work, it broadcasts the block to all nodes.
5) Nodes accept the block only if all transactions in it are valid and not already spent.
6) Nodes express their acceptance of the block by working on creating the next block in the chain, using the hash of the accepted block as the previous hash.

Nodes always consider the longest chain to be the correct one and will keep working on extending it. If two nodes broadcast different versions of the next block simultaneously, some nodes may receive one or the other first. In that case, they work on the first one they received, but save the other branch in case it becomes longer. The tie will be broken when the next proof-of- work is found and one branch becomes longer; the nodes that were working on the other branch will then switch to the longer one.

比特幣網絡

比特幣網絡的運作方式如下:

1)新的交易會向通知所有節點義工。
2)每個節點將新的交易紀錄到一個區塊中。
3)每個節點各自尋找一個複雜(即最可信)的「工作量證明」。
4)當一個節點滿足於某個「工作量證明」時,它將這「驗證」廣播到所有節點。
5)只當區塊中的所有交易都有效並且沒有重複支付時,節點才接受該區塊。
6)當節點接受一個區塊後,它們會在它之上建立另一個區塊,連成一條鍵,並將之前的區塊的“指纹”紀錄在新區塊內。

節點若在相近的一段很短時間內收到兩個「工作量證明」,它們會將其保留一段時間,以便比較出最長的分支,接納其為最新的區塊鍵。

6. Incentive

By convention, the first transaction in a block is a special transaction that starts a new coin owned by the creator of the block. This adds an incentive for nodes to support the network, and provides a way to initially distribute coins into circulation, since there is no central authority to issue them.

The steady addition of a constant of amount of new coins is analogous to gold miners expending resources to add gold to circulation. In our case, it is CPU time and electricity that is expended. The incentive can also be funded with transaction fees. If the output value of a transaction is less than its input value, the difference is a transaction fee that is added to the incentive value of the block containing the transaction. Once a predetermined number of coins have entered circulation, the incentive can transition entirely to transaction fees and be completely inflation free. The incentive may help encourage nodes to stay honest. If a greedy attacker is able to assemble more CPU power than all the honest nodes, he would have to choose between using it to defraud people by stealing back his payments, or using it to generate new coins. He ought to find it more profitable to play by the rules, such rules that favour him with more new coins than everyone else combined, than to undermine the system and the validity of his own wealth.

報酬

按慣例,區塊中的第一個交易創造者(交易商,或掘金者,在這裡兩者大致是同一種東西)可以得到一個新的硬幣。這是它的報酬,同時也增加比特幣進入流通。

新的硬幣數量的不斷增加與淘金者不斷增添黃金進入流通相似。在我們這種情況下,黃金就這是CPU時間和耗電量。交易商若成功制作並被接納一個區塊時,可賺取12.5個比特幣( 隨周期減半,註6)和交易費。

交易商賺取交易差額,或它可以豁免交易費。當一定數量的硬幣進入流通後,交易商可以收取全部費用,比特幣是沒有通貨膨脹現象的。

獎勵有助於鼓勵節點誠實。如果一個貪婪的攻擊者能夠組裝比所有誠實節點更多的CPU電源,他可以選擇用它來產生新的硬幣,這會比來用它來竊取別人的硬幣更佳。這樣的規則有利於他獲得更多的新硬幣,而不是破壞系統和自己的財富。

7. Reclaiming Disk Space

Once the latest transaction in a coin is buried under enough blocks, the spent transactions before it can be discarded to save disk space. To facilitate this without breaking the block’s hash, transactions are hashed in a Merkle Tree [7][2][5], with only the root included in the block’s hash. Old blocks can then be compacted by stubbing off branches of the tree. The interior hashes do not need to be stored. A block header with no transactions would be about 80 bytes. If we suppose blocks are generated every 10 minutes, 80 bytes * 6 * 24 * 365 = 4.2MB per year. With computer systems typically selling with 2GB of RAM as of 2008, and Moore’s Law predicting current growth of 1.2GB per year, storage should not be a problem even if the block headers must be kept in memory.

節省儲存空間

當區塊鍵建到某一長度時,其之前的區塊可以刪去以節省空間又不降低其完整性。這裡用上了一種數學樹的同步數據一致性的算法。由於區塊鍵的增長速度低於儲存芯片的增長速度。預計電腦不會因為區塊鍵的增長而無法運作。

8. Simplified Payment Verification

It is possible to verify payments without running a full network node. A user only needs to keep a copy of the block headers of the longest proof-of-work chain, which he can get by querying network nodes until he’s convinced he has the longest chain, and obtain the Merkle branch linking the transaction to the block it’s timestamped in. He can’t check the transaction for himself, but by linking it to a place in the chain, he can see that a network node has accepted it, and blocks added after it further confirm the network has accepted it. As such, the verification is reliable as long as honest nodes control the network, but is more vulnerable if the network is overpowered by an attacker. While network nodes can verify transactions for themselves, the simplified method can be fooled by an attacker’s fabricated transactions for as long as the attacker can continue to overpower the network. One strategy to protect against this would be to accept alerts from network nodes when they detect an invalid block, prompting the user’s software to download the full block and alerted transactions to confirm the inconsistency. Businesses that receive frequent payments will probably still want to run their own nodes for more independent security and quicker verification.

簡化交收核算

核實交易是否成功,用者不需要在其電腦上運行整固節點程式。這需要每月`詢。他不能自行查冊交易詳情,但他可以了解其他節點是否接受了這一區塊。由於區塊鍵的安全性是建基於大多數節點為誠實,其保安措施為:當某個節點發現可疑區塊時,它會向其他節點發預警。

9. Combining and Splitting Value

Although it would be possible to handle coins individually, it would be unwieldy to make a separate transaction for every cent in a transfer. To allow value to be split and combined, transactions contain multiple inputs and outputs. Normally there will be either a single input from a larger previous transaction or multiple inputs combining smaller amounts, and at most two outputs: one for the payment, and one returning the change, if any, back to the sender. It should be noted that fan-out, where a transaction depends on several transactions, and those transactions depend on many more, is not a problem here. There is never the need to extract a complete standalone copy of a transaction’s history.

比特幣的整合和拆細

為了方便支付,比特幣可以整合和拆細。其方法是將交易分為多個輸入和輪出。通常地,一筆大交易只有一個輸出口,一堆細交易則由多個輸入點整合。它會將找找贖退回給付款者。比特幣可以解決複雜交易。它不需要知道完整的交易歷史。

10. Privacy

The traditional banking model achieves a level of privacy by limiting access to information to the parties involved and the trusted third party. The necessity to announce all transactions publicly precludes this method, but privacy can still be maintained by breaking the flow of information in another place: by keeping public keys anonymous. The public can see that someone is sending an amount to someone else, but without information linking the transaction to anyone. This is similar to the level of information released by stock exchanges, where the time and size of individual trades, the “tape”, is made public, but without telling who the parties were. As an additional firewall, a new key pair should be used for each transaction to keep them from being linked to a common owner. Some linking is still unavoidable with multi-input transactions, which necessarily reveal that their inputs were owned by the same owner. The risk is that if the owner of a key is revealed, linking could reveal other transactions that belonged to the same owner.

私隱

傳統交易中介如銀行會保障客人的一定私隱,但比特幣公開了所有交易歷史。比特幣的保障私隱的方法是將資料分拆,收起公開鑰匙。在比特幣中,公眾獲悉每筆交易的流量、時間等,但不會知道交易者的身份。這和證券市場的作法相若。進一步,在每次交易裡,一套新的鑰匙交給比持幣持有人,令人們無法將該人的其他交易連繫跟蹤。它還有一些私隱隱患的,若持有人的鑰匙被別人得悉,他的交易有可能被別人查到。

Calculations

We consider the scenario of an attacker trying to generate an alternate chain faster than the honest chain. Even if this is accomplished, it does not throw the system open to arbitrary changes, such as creating value out of thin air or taking money that never belonged to the attacker. Nodes are not going to accept an invalid transaction as payment, and honest nodes will never accept a block containing them. An attacker can only try to change one of his own transactions to take back money he recently spent. The race between the honest chain and an attacker chain can be characterized as a Binomial Random Walk. The success event is the honest chain being extended by one block, increasing its lead by +1, and the failure event is the attacker’s chain being extended by one block, reducing the gap by -1. The probability of an attacker catching up from a given deficit is analogous to a Gambler’s Ruin problem. Suppose a gambler with unlimited credit starts at a deficit and plays potentially an infinite number of trials to try to reach breakeven. We can calculate the probability he ever reaches breakeven, or that an attacker ever catches up with the honest chain, as follows [8]: p = probability an honest node finds the next block q = probability the attacker finds the next block qz = probability the attacker will ever catch up from z blocks behind qz={ 1 if p≤q q/ pz if pq} 6 Identities Transactions Trusted Third Party Counterparty Public Identities Transactions Public New Privacy Model Traditional Privacy Model Given our assumption that p > q, the probability drops exponentially as the number of blocks the attacker has to catch up with increases. With the odds against him, if he doesn’t make a lucky lunge forward early on, his chances become vanishingly small as he falls further behind. We now consider how long the recipient of a new transaction needs to wait before being sufficiently certain the sender can’t change the transaction. We assume the sender is an attacker who wants to make the recipient believe he paid him for a while, then switch it to pay back to himself after some time has passed. The receiver will be alerted when that happens, but the sender hopes it will be too late. The receiver generates a new key pair and gives the public key to the sender shortly before signing. This prevents the sender from preparing a chain of blocks ahead of time by working on it continuously until he is lucky enough to get far enough ahead, then executing the transaction at that moment. Once the transaction is sent, the dishonest sender starts working in secret on a parallel chain containing an alternate version of his transaction. The recipient waits until the transaction has been added to a block and z blocks have been linked after it. He doesn’t know the exact amount of progress the attacker has made, but assuming the honest blocks took the average expected time per block, the attacker’s potential progress will be a Poisson distribution with expected value: =z q p To get the probability the attacker could still catch up now, we multiply the Poisson density for each amount of progress he could have made by——。

數學方法

讓我們想像有盜幣者想攻擊區塊鍵,就算他有能力比誠實的區塊鍵的生長速度更快,誠實大多數的節點仍然不會接受它制做出的區塊鍵,節點會分辨出虛構出來的交易。

盜幣者唯一的方法是運用詐騙手法,收回自己剛剛支付的比特幣。但在這個速度競賽中,盜幣者的成功機會很低。

12. Conclusion

We have proposed a system for electronic transactions without relying on trust. We started with the usual framework of coins made from digital signatures, which provides strong control of ownership, but is incomplete without a way to prevent double-spending. To solve this, we proposed a peer-to-peer network using proof-of-work to record a public history of transactions that quickly becomes computationally impractical for an attacker to change if honest nodes control a majority of CPU power. The network is robust in its unstructured simplicity. Nodes work all at once with little coordination. They do not need to be identified, since messages are not routed to any particular place and only need to be delivered on a best effort basis. Nodes can leave and rejoin the network at will, accepting the proof-of-work chain as proof of what happened while they were gone. They vote with their CPU power, expressing their acceptance of valid blocks by working on extending them and rejecting invalid blocks by refusing to work on them. Any needed rules and incentives can be enforced with this consensus mechanism

結論

比特幣解決了電子支付在沒有第三方保證的雙重支付問題。解決的方法是在點對點網絡上運用“工作量證明”來紀錄所有比特幣交易。在攻防戰中,盜幣者很快被誠實的節點打破。比特幣網絡簡單實用,節點共同協作但不用高度統一。節點作為義工,不用表露身份,因為交易訊息不是指向特定地點,而且,只有最好的區塊被傳播出去。節點可以隨時加入或退出。它們是一節點一票,不會接受偽造區塊鍵。它們在共識之下生存。

附錄:
註一中國人民銀行公告第17號〔2016〕
根據《非金融機構支付服務管理辦法》(中國人民銀行令〔2010〕第2號發佈)、《中國人民銀行關於〈支付業務許可證〉續展工作的通知》(銀髮〔2015〕358號),中國人民銀行對27家非銀行支付機構(以下簡稱支付機構)《支付業務許可證》續展申請作出決定(見附件)。現將有關事項公告如下:
一、本次《支付業務許可證》續展有效期為五年,截止日期為2021年5月2日。
二、為整合業務資源,發揮規模效應,提高監管效率,本次續展對擬合併《支付業務許可證》的支付機構,相應調整其業務範圍。
被合併支付機構應於公告之日起6個月內完成支付業務承接工作。中國人民銀行將在業務承接工作完成後,辦理相關《支付業務許可證》的註銷、換發事宜。
三、因部分支付機構存在業務嚴重違規、業務停滯萎縮或主動申請終止業務類型等情形,本次續展調減其業務範圍。相關機構應於公告之日起6個月內按要求有序停止開展相關支付業務。
四、中國人民銀行將繼續依法、審慎開展《支付業務許可證》續展工作。對於長期未實質開展支付業務的支付機構,中國人民銀行將依法採取取消相關業務種類、註銷《支付業務許可證》等監管措施;對於存在嚴重違法違規行為的支付機構,將嚴格依據相關法律法規予以查處,以保障支付服務市場規範有序發展。
中國人民銀行
2016年8月11日
附件:27 家非銀行支付機構《支付業務許可證》續展

註二
人民銀行發佈《非銀行支付機構網路支付業務管理辦法

中國人民銀行公告〔2015〕第43號
為規範非銀行支付機構網路支付業務,防範支付風險,保護當事人合法權益,中國人民銀行制定了《非銀行支付機構網路支付業務管理辦法》,現予發佈實施。
附件:非銀行支付機構網路支付業務管理辦法

註三

與集中支付體系相比,區塊鏈轉帳支付交易可以在雙方直接進行,不涉及中間機構,也可以通過支付服務商,如比特幣兌換主權貨幣通過交易平臺,這些交易平臺業務性質類似於銀行,提供帳戶既包含主權貨幣、比特幣,交易時只改變帳戶數量資訊,沒有發生實質上的區塊鏈交易移動,因此不管哪類交易情況下部分網路癱瘓也不影響整個系統運行,在資料傳遞和記帳登記上穩定性高於雙中心的架構。

中國支付清算》—中國支付清算協會

註四

http://m.mpaypass.com.cn/news/201708/04162524.html
http://m.21jingji.com/article/20170804/herald/ccb9e223a63c71d59231beb633aa4723.html
通知表示,人民銀行指導支付清算協會建設“非銀行支付機構網路清算平臺”(簡稱“網聯平臺”),主要處理支付機構發起的涉及銀行帳戶的網路支付業務。現就網路支付業務由支付機構與銀行直連模式遷移至網聯平臺處理有關事項通知如下:
一、自2018年6月30日起,支付機構受理的涉及銀行帳戶的網路支付業務全部通過網聯平臺處理。
二、各銀行和支付機構應於2017年10月15日前完成接入網聯平臺和業務遷移相關準備工作。
三、網聯平臺運營機構應制定實施計畫,組織各銀行和支付機構妥善做好接入工作,包括聯調測試、生產驗證、壓力測試和存量協定遷移等,並提供相關業務、技術支援。
四、各銀行和支付機構應高度重視,加強組織協調,按照計畫完成相關工作。指定專人負責工作對接,並於8月15日前將連絡人名單回饋人民銀行支付結算司。
五、請人民銀行各分支機搆支付結算處速將本通知轉發至轄區內各銀行和支付機構,指導並督促其認真做好接入網聯平臺和業務切量工作

註五

3. NEW PAYMENT SYSTEMS
As detailed in the National ML Risk Assessment, virtual currencies such as Bitcoin and other emerging payments technologies, while representing an opportunity for financial innovation, have attracted the attention of various criminal groups, and may be vulnerable to abuse by terrorist financiers. For example, the U.S. Secret Service has observed that criminals are looking for and finding virtual currencies that offer anonymity for both users and transactions; the ability to move illicit proceeds from one country to another quickly; low volatility, which results in lower exchange risk; widespread adoption in the criminal underground; and trustworthiness.282 In terms of TF risk, there has been some speculation about using virtual currency to transfer funds overseas. For example, a posting on a blog linked to ISIL has proposed using Bitcoin to fund global jihadist efforts.

註六

Bitcoin just experienced a major milestone in its short little lifespan. The reward for mining a block (a block = a ledger of transaction data) was just cut in half from 25 bitcoins to 12.5 bitcoins.

So, today was the second ever halving in the history of Bitcoin. The first halving (when the reward was cut from 50 to 25 bitcoins) was back in November of 2012, when the price was around $12 dollars.

註七

Minimum Requirements
Bitcoin Core full nodes have certain requirements. If you try running a node on weak hardware, it may work—but you’ll likely spend more time dealing with issues. If you can meet the following requirements, you’ll have an easy-to-use node.

Desktop or laptop hardware running recent versions of Windows, Mac OS X, or Linux.
145 gigabytes of free disk space
2 gigabytes of memory (RAM)
A broadband Internet connection with upload speeds of at least 400 kilobits (50 kilobytes) per second
An unmetered connection, a connection with high upload limits, or a connection you regularly monitor to ensure it doesn’t exceed its upload limits. It’s common for full nodes on high-speed connections to use 200 gigabytes upload or more a month. Download usage is around 20 gigabytes a month, plus around an additional 140 gigabytes the first time you start your node.
6 hours a day that your full node can be left running. (You can do other things with your computer while running a full node.) More hours would be better, and best of all would be if you can run your node continuously.
Note: many operating systems today (Windows, Mac, and Linux) enter a low-power mode after the screensaver activates, slowing or halting network traffic. This is often the default setting on laptops and on all Mac OS X laptops and desktops. Check your screensaver settings and disable automatic “sleep” or “suspend” options to ensure you support the network whenever your computer is running.

(圖片來源:youtube截圖)

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