Recently Online emerge from time to time a new term "block chain" curiosity more than many articles on the Internet chops, went to great lengths, finally met a ballpark. The following non-professional in their own language to try to interpret, to give small series share the same block chain that is too difficult to understand partners.
Block chain is a kind of the same technology and the use of BT download P2P peer network technology
The so-called block chain technology, referred to as BT (Blockchain technology), also known as distributed technology books, is an Internet database technology, which is characterized by decentralized, open and transparent, so that everyone can participate in the database record. [From Baidu Encyclopedia]
These are the definition of block chain, we can see a familiar shorthand term "BT", we know, bt download a downloader all computers can be used as a staging server, to share their files on the network needs people to download. I think we can first determine a concept: the block chain is a kind of the same technology and the use of BT download P2P peer network technology. So, you can start small series below tell you more familiar with BT download mechanism from these concepts and then transition to block chain technology above.
For ease of understanding, assume there are four students: Xiaodong, Fang, Xiao Ming, beads, they are ordinary Internet users located in different areas of their computer that are the same bt client installed. bt download requires a server to store some public information distribution, this server is called a tracker server. When we read the following, to remember "bt client" and "tracker server," probably meaning of these two terms. Recommended content read this paragraph again, we will remember the profound enough to ensure the smooth understanding behind the content.
bt download a flow chart
Assume Xiaodong students find a bt seed on the Internet, a movie, he opened with seed and start downloading the client bt, bt client first connects the tracker, the tracker based on information bt seed, analyze the film is divided into four parts ABCD, which has been downloaded the small side AC two parts, Xiao Ming downloaded BD in two parts, and the beads are downloaded the complete file of the film. So tracker server to a small square, Xiao Ming, beads movie addresses are told bt client Xiaodong, and then a small East bt client to embark on these addresses, directly connected to the small square, Xiao Ming, beads of computers, from their computer to download the film.
Visible, BT download among the movie file is not required on a dedicated server, but on all those involved in downloading personal computer. bt server only as an organizer for recording and distributing information of those who download, download, download progress, but also it can be understood as a "intermediary" or such a role, "matchmaker", from matchmaking role. This file is stored in the users computer technology, it is the "distributed file storage." File Block chain technology also used this "distributed file storage" program, but it is usually stored in a database file, rather than movies or music like we often download.
(Note: Since this scenario, the status of all Internet users in bt download are equal, so this network structure is said to "P2P peer.")
Block chain with BT download more important difference between the two: a distributed and decentralized books
"Distributed books" block chain concepts
The objective is bt download movies, music and the like fixed content resource file, and the content "distributed books" is a constantly changing, this is the most obvious difference between the two. To understand the process of change of the books, the figure shows three analog form, location mimic bitcoin chain books. Table 1 is stored in the balance of the original recording (have a copy of this form per person, because it is encrypted, who can not be modified without permission and decryption). Now Xiaodong Xiao Ming and trade, Xiaodong the 20 bitcoin transferred to Xiao Ming. Table 2 is recorded under the trading process and the final balance results, and Table 3 the only record the final balance. For involved in the transaction and Xiaodong Xiao Ming, the Table 2 in the transaction information to be useful, they will choose to keep [Table 2], while for small parties and beads, the others deal has nothing to do with their own, only the need to retain the result table [3] on it. But in fact, Table 2 and Table 3 are recorded for all of the latest balance. Chain location application, which is basically similar in such a way, through the P2P network, distributed transaction and record the results, to achieve its purpose of application. Thus I think we can extend a theoretical concept: regional chain technology as long as there is a computer keeps running, the whole bit chain region will never be effective.
Bitcoin trading simulation books
"Decentralized" block chain
We know, bt download requires a tracker server as an intermediary, to those who download the online matchmaking, not the server, bt download can not be completed. The regional chain Every member has a copy of the books, which records information on all members of the balances and contact information, so, in theory, every member of computers, can be used as a server, that is, no other server as the "intermediary", which is an important feature of regional chain technology - "to the center." FIG still lower bit trading credits as an example, will be mainly described block chains "decentralized" feature. All transactions are visible through the P2P peer to achieve, and parties to the transaction by the free market in the online or offline, exchanges, circles and other occasions to recognize and deal transactions will and does not require a separate server center to matchmaking. This is still a theoretical concept: regional chain technology as long as there is a computer keeps running, the whole bit chain region will never be effective.
Bitcoin transaction flow diagram of decentralized
Consensus mechanism block chain
区块链的共识机制，就是所有记账节点之间怎么达成共识，去认定一个记录的有效性，这既是认定的手段，也是防止篡改的手段。仍以上面的比特币交易为例进行说明。小东和小明通过某种渠道认识，并达成交易，小东要把20个比特币转给小明。注意区块链不需要服务器，但是也需要一个客户端，这个客户端的作用，就是把这个交易发送到P2P网络上，当它寻找到小方的电脑，就会把这个交易交给小方去验证。小方验证了小东和小明的余额有效，可以合法交易后，再把这个交易发送给小珠，小珠再接着确认。就这样以一传十，十传百的方法，寻找更多的人来验证这个交易。（至于客户端如何寻找小方、小珠，可参考有关”P2P节点发现“的相关知识，在这里不再详细说明）。当验证的人数（节点）达到一定的规模后，这个交易才正式生效。而由于小东有足够的余额（100），所以他的交易本身是合法有效的，而小方的电脑里，也记录着小东的余额，因此也一定会认为此交易有效。最终，所有人都同意这个交易是有效的，并各自更新自己电脑里的余额记录。当下一次再有人发起交易时，大家就用新的记录去验证新的交易是否有效。以上说明的就是区块链的共识机制。有了这个机制，任何人私自更改自己的记录，都不可能得到超过51%的人的认同（因为算法复杂并涉及自身利益等，在此不详细说明）。
区块链的加密技术
区块链采用公钥、私钥进行非对称加密和解密，具体原理这里不详述，仍以上述比特币交易的例子进行说明：
Xiaodong take 20 Bitcoin transferred to Xiao Ming, Xiao Ming told his own public Xiaodong, 20 Bitcoin Xiaodong information encrypted with the public key, and then sent back to Bob. After Bob obtain this information, then this information to decrypt the private key, resulting in 20 bits Xiaodong credits. This process is very complicated, as long as you remember only the public key encryption, can not decrypt it. Public means public, all people are likely to get. While the private key is kept by the individuals themselves, and not let other people know. When verify the ownership, but also through public key cryptography, you can see where you can verify the public key part, but if there is no corresponding private key, others will not be able to decrypt the contents inside. Block chain is through such a mechanism to ensure the safe operation and transaction signature process personal information or property. Bit encryption technology chain is very complex area, it can only give a brief introduction.
to sum up
This article is to explain the remarkable light scenarios and features regional chain technology, it is impossible getting to the bottom, because the theory they involve much more profound than paper, hoping for beginners, will reap some basic understanding.
Reproduced in: https: //my.oschina.net/u/1458864/blog/3060338