通俗易懂，到底什么是区块链？

2017年9月4日，中国政府正式明令禁止ICO和数字货币交易行为，随即关闭了多个数字货币交易所。同时政府也多次声明，不会将区块链与数字货币划等号，依然非常重视区块链技术在中国的发展。随后，中国工业和信息化部成立了一个专门研究区块链的实验室——可信区块链开放实验室，进一步明确政府对区块链技术发展的重视和支持。

& #xff0c September 4th, 2017; the Chinese government officially and explicitly banned ICO and digital currency transactions & #xff0c; and immediately shut down several digital currency exchanges. Meanwhile, the government has repeatedly stated & #xff0c; does not equate block chains with digital currencies & #xff0c; continues to attach great importance to the development of block chain technology in China.

什么是区块链？

What is a block chain #xff1f;

区块链技术源于比特币，是比特币底层支撑技术。中国政府禁止比特币交易主要是担心数字货币交易带来的金融风险，以及避免不法人士利用数字货币交易的法律漏洞设计交易骗局。但区块链是一种技术，可以让交易突破传统的信任交易模式和集中化架构，实现非安全环境下的交易安全。由于区块链技术能解决传统互联网交易过程中面临的诸多问题，近年来得到了各国政府及企业的广泛关注。目前，对于区块链技术很多网站都有详细的解释，但由于过于专业，很难让人理解，现在我们以一种通俗易懂的方式来帮助读者解读什么区块链？

The Chinese government prohibits bitcoin transactions mainly because of concerns about the financial risks associated with digital currency transactions & #xff0c; and avoids the use of legal loopholes in digital currency transactions by outlaws to design trade scams. But block chains are a technology & #xff0c; they allow transactions to break through traditional modes of trust transactions and centralized structures & #xff0c; they provide security for transactions in unsafe environments. Because block chain technologies can solve many of the problems faced by traditional Internet transactions xff0c; they have received extensive attention from governments and businesses in recent years. xff0c; there are many web sites with detailed explanations for block chain technologies xff0c; it is difficult to understand xff0c; now we can help readers to read what chains xff1f in a user-friendly way;

简单来说，区块链就是一个分布式账本，通过去中心化、去信任的方式集中维护一个可靠的数据库。以支付宝交易为例，传统的交易方式是买家在淘宝平台购买商品，然后将购买商品的钱打到支付宝这个中介平台，待卖方发货以及买方确认收到货之后，再由买方通知支付宝将钱打到卖方账户。但区块链技术支撑的交易模式完全不同，买家和卖家可直接进行交易，不需要通过任何中间平台做信用交易，交易后系统通过广播的形式将交易信息发布到P2P网络中，所有收到交易信息的节点或主机会在确认信息无误后记录下这笔交易。这就相当于所有的节点主机都为这边交易做了数据备份，即便某一台机器出现宕机、系统崩溃、木马攻击和数据篡改等情况也不会影响数据的记录，因为还有无数台机器作为备份。

Simplely xff0c; block chain is a distributed account book xff0c; centralized maintenance of a reliable database by means of decentralizing and trusting; payment of treasures is the case xff0c; the traditional way of dealing is for buyers to buy goods xff0c on a pedagogic platform; then the money to buy goods is paid on an intermediary platform xff0c; the transaction information is posted in the form of a broadcast to the P2P network xff0c; and all nodes or masters who receive the transaction information have a different mode of trading xff0c; buyers and sellers can directly trade xff0c; credit transactions xff0c are not required to be made through any intermediary platform; the post-trading system distributes the transaction information to the P2P network xff0c; and all the nodes or masters who receive the transaction are able to record the transaction after confirmation of the information.

从数据的角度讲，区块链是一种几乎不可能被更改的分布式数据库，这种分布式不仅体现在存储架构上，也体现在分布式记录，即由系统参与者共同维护。从技术的角度讲，区块链并不是单一的技术，而是多种技术的复合体，包括分布式存储、数字签名和P2P网络架构等。

From a data point of view xff0c; blocks chain is a distributional database xff0c, which is almost impossible to change; this distribution is reflected not only in the storage structure xff0c; it is also in distributed records xff0c; i.e. it is maintained jointly by system participants. From a technical point of view xff0c; blocks chain is not a single technology xff0c; it is a multi-technology complex xff0c; it includes distributed storage, digital signatures and P2P network structures.

区块链的工作原理

The working principles of the block chain

区块链的数据存储方式其实就是“区块”+“链”。这就好比我们的日记本，每一页都是一张纸，纸上可以记录有用文字信息，但每一页都会有页码，记录每页文字所处的顺序。对比来说，区块就是“纸”，用来记录创建期间发生的所有价值交换活动。页码就是“链”，按照时间先后顺序将区块存储在数据库中。

The chain of blocks is actually stored in the form of blocks & #43; chains. This is like our journal & #xff0c; each page is a piece of paper & #xff0c; it records useful text information & #xff0c; but each page has a page number & #xff0c; records the order in which each page is written. In contrast, xff0c; blocks & #xff0c; records all value exchange activities that take place during creation. The page number is the “chain” #xff0c; store blocks in the database in chronological order.

那么或许你就要问，那么多节点到底选择有谁来优先记录区块信息？其实很简单，就是谁最先完成记录就以谁为准。如图1所示，如果老张和老李要进行一笔交易，就会产生一笔账单记录，账单记录会显示付款人信息、收款人信息、交易的内容以及当前所处的链条序列。在交易完成后，区块链系统会将本次交易清单与上一账单编号的数据进行加密之后发布到全网所有的节点，也就是接入网络中的每一台主机，所有节点在收到公告账单信息后会争夺第一记账权，这一过程包括验证交易双方的信息，在得到确认之后更新账簿，以第一个完成账单记录的节点为准。因此，一旦第一个记账完成，所有节点只能接收记账信息并更新本地账簿，这就是共识机制。

Then perhaps you will ask xff0c; if so many nodes choose who will give priority to recording block information xff1f; if so, it is simple xff0c; whichever is the first person to complete the record. As shown in figure 1 xff0c; if Chang and Li are to make a transaction xff0c; if all nodes are received with the billing information xff0c; if the bill records show the payee's information, the recipient's information, the content of the transaction and the chain sequence in which it is currently located. This process includes verifying the information of the parties xff0c; updating the books after confirmation xff0c; completing the first account log xx0c; thus, every host in the network xff0c; and once the accounts 0x

由于每笔账单交易的记录都包含上一个链条的信息，因此一旦某一条交易记录被篡改就自然会出现信息错误或上下链条信息部匹配，而且容易出现链条分叉，因此，采用区块链技术记录的数据篡改难度几乎不可能，数据的容错性极高。而且由于所有账单交易数据的公布都是以加密的方式在网络中发送，要想在网络中篡改数据就必须至少截获51%以上的节点数据并在极短的时间内破解，这种情况可以认为几乎没有可能。

Since the records of each bill transaction contain information from the previous chain xff0c; therefore, once a transaction record has been tampered with, information errors or top-down chain information matches xff0c; xff0c; thus xff0c; data manipulation difficulties using block-chain technical records are almost impossible xff0c; data tolerance is extremely high; and since all bill transaction data are published in an encrypted way on the web xff0c; it is necessary to intercept at least 51 per cent of the node data and decrypt xff0c in a very short period of time if the data are to be tampered with in the network; this is hardly possible.

区块链发展存在哪些瓶颈？

What are the bottlenecks in block chain development? #xff1f;

从2009年比特币出现，区块链技术的发展时间还比较短，各种层次的应用研究仍然在不断深入的过程中。但由于区块链突破的传统的集中式数据防护架构以及非信用的安全模式，其应用依旧存在着一定的安全局限，从技术层和业务层都面临诸多挑战。

The emergence of xff0c in Bitcoin in 2009; the development of block chain technology is relatively short xff0c; application studies at various levels are still in the process of deepening. Traditional centralized data protection structures and non-credit security models xff0c have broken through block chains; their applications still have some security limitations xff0c; and there are many challenges from both technical and operational levels.

首先，共识机制的挑战。区块链中的共识算法是否能实现并保障真正的安全，需要更严格的证明和时间的考验。采用的非对称加密算法可能会随着数据、密码学和计算技术的发展而变的越来越脆弱，未来可能具有一定的破解性。此外，区块链上包含账户安全的私钥是否容易窃取仍待进一步探索。

First & #xff0c; the challenge of consensus mechanisms. Whether consensus algorithms in block chains achieve and guarantee real security & #xff0c; and the need for stricter proof and time tests. Asymmetric encryption algorithms may become increasingly fragile as data, cryptography and computing techniques develop & #xff0c; the future may be somewhat deconstructive. And #xff0c; and whether private keys in block chains containing account security are easy to steal are still to be explored further.

其次，51%攻击是否能突破。在比特币中，若控制节点中绝大多数计算资源，就能重改公有账本，这被称为51%攻击。真实的区块链网络是自由开放的，所以，理论上，区块链上无法阻止拥有足够多计算资源的节点做任何操作。在现实情况下，发起51%攻击是具有一定可行性的。当然，拥有足够的算力并不会迅速破坏整个体系——至少不是短时间内，但可能会导致系统混乱。

Second xff0c; 51% whether the attack is broken. In bitcoin, xff0c; if the majority of computing resources in the node are controlled xff0c; if the vast majority of computing resources in the node are controlled xff0c; this is called 51% attack. The real block chain network is free xff0c; so xff0c; theoretically xff0c; there is no way to prevent any action on the node with sufficient computing resources. In reality, xff0c; the launching of 51% of the attack is feasible.

第三，N@S攻击。针对PoW共识算法容易遭受51%攻击的问题，一些研究人员对PoW共识算法进行了改进，但在解决旧有问题的同时，也引入了区块分叉时的N@S（Nothingatstake）攻击问题。比如，在某些情况下一个区块可以暂时拥有两个子区块。这种分叉状态出现时，一般是两个矿工都在短时间内发现了工作量的解答，然后将所添加的传播到临近网络中去，其他节点便慢慢形成两种版本（子区块）的区块链。区块链中规定，这种情况下的判定条件是选择工作总量最大的那条子区块。出于自身利益最大的考虑，节点上可以同时在两个分支上继续工作，以保证利益的获取。假设99%的节点用户都如此理性地考虑收益的话，即便攻击者只掌握1%的权益依旧可以决定区块链的分支走向。他可以发出交易请求，获得资产，然后再从另一条分支上获取添加货币到自己的钱包中。

Third xff0c; N~64; S attack. Questions against PoW consensus algorithms that are vulnerable to 51% attacks xff0c; some researchers have improved the PoW consensus algorithms xff0c; but while resolving old problems xff0c; N64; Sff08; Nothingastake） attack problems. e.g. xff0c; in some cases a block can temporarily have two sub-blocks xff0c; in others, two sub-blocks xff09; in the sector chain xff0c; in this case, two miners have found a solution to the workload xff0c; in the case of two miners xx x

此外，区块链也存在一些难以克服的不足：效率问题。区块链没有单一节点可信任，通过计算来换取信任。简单的一个承认交易操作，需要大量的计算参与进来。比如匿名引发的风险。区块链开发者认为匿名性在区块链交易中是重要的，并非“抗审查”。如果矿工决定不处理某笔交易在地址间的收发，那就证明交易是受矿工审查的。如果交易是匿名的，矿工就不能决定优先处理哪些交易，也就不能进行审查。但匿名性会造成非法交易的猖獗，执法部门很难溯源。

In addition, xff0c; block chains have a number of insurmountable deficiencies xff1a; efficiency problems. There is no single node in the block chain to trust xff0c; trust to calculate. A simple acknowledged transaction operation xff0c; a large number of calculations are required to participate. For example, anonymous risks. Block chain developers consider anonymity to be important in block chain transactions xff0c; not “resistance”. If miners decide not to process a transaction between addresses xff0c; prove that the transaction is subject to review by miners. If the transaction is anonymous xff0c; miners cannot decide which transactions xff0c; nor can they be reviewed. But anonymity can lead to a proliferation of illegal transactions xff0c; law enforcement is difficult to trace.

结束语

Concluding remarks

尽管存在一定的安全局限和难以克服的不足，但区块链技术提供了一个规模化的共识机制，可以作为一种更高效解决信任问题的手段，建立去中心化的可信网络。目前，区块链的应用已从单一的数字货币（如比特币）应用，延伸到经济社会的各个领域，除金融服务行业的应用相对成熟外，其他行业的应用还处于探索起步阶段，期待区块链技术的更新和完善。

Despite certain security constraints and insurmountable deficiencies xff0c; the block chain technology provides a consensus mechanism of scale xff0c; it can be used as a more efficient means of resolving trust issues xff0c; it creates a credible network that is decentralised. Currently xff0c; the block chain has been applied from a single digital currency xff08; e.g. Bitcoinxff09; the application xff0c; the extension to various areas of the economy xff0c; xff0c, in addition to the relatively mature application in the financial services industry; applications in other industries are still in the initial stages of exploration xff0c; and the updating and refinement of block chain technology is expected.