区块链系统篡改不了怎么办,区块链系统篡改不了数据

当今社会，区块链系统已经成为了重要的技术，它可以保护用户的数据安全，防止篡改。但是如果发生了篡改，那么怎么办呢？这里介绍的是三种处理篡改的方法：

一、多签名技术：多签名技术是一种技术，它可以使用多个签名来确保数据的安全性。例如，一个公司有多个账号，只有多个账号中的一部分签名才能够进行交易，这就可以防止篡改。

二、智能合约：智能合约是一种利用区块链技术来执行特定的智能合约的技术。它可以确保交易的准确性和完整性，防止篡改。智能合约可以在区块链上执行，以确保交易的安全性，这样就可以防止篡改。

三、共识机制：共识机制是一种利用一组参与者来确认交易的技术。它可以在区块链网络上运行，以确保数据的准确性和完整性，从而防止篡改。共识机制可以确保交易的安全性，这样就可以防止篡改。

总而言之，当发生篡改时，应该采用多签名技术、智能合约和共识机制来保护数据的安全性，防止篡改。只有这样，才能确保区块链系统的安全性，保护用户的数据安全。

1. How to correctly understand the non-tampering characteristics of blockchain technology

The analysis of Chongqing Jinwowo Network is as follows:
Based on the characteristics of decentralization , even if the blockchain suffers a serious hacker attack, as long as the number of nodes controlled by hackers does not exceed half of the total number of global nodes, the system will still be able to operate normally and the data will not be tampered with.
This is a distributed data storage based on blockchain. Because there is no centralized management center, even if a node is attacked or tampered with in the blockchain system, it will not affect the health of the entire network. operation.
Because the rights and obligations of all nodes are equal, and activities will be supervised by the entire network. At the same time, each of these nodes has the ability to vote using computing power, which ensures that the recognized result is the result recognized by more than half of the nodes.

2. Why the regional chain cannot modify more than 51% of the nodes at the same time

Everyone should understand the basic definition of blockchain. To put it bluntly, everyone keeps accounts together, one block The chain system consists of many nodes, which are usually computers. In this system, each participating node has the opportunity to compete for accounting, that is, to update database information. The system will select the node with the fastest and best accounting within a period of time (it may be ten minutes, or it may be one second), and let it record accounts within this period of time. Data changes are recorded in a data block.

We imagine this block of data as a page. After completing the accounting, the node will send this page of the ledger to other nodes. Other nodes will verify whether this page of ledger is correct, and if there is no problem, it will be put into their own ledger. In the system, the data representation of this page of the ledger is called a block. This block records the changes in the entire ledger data during this period. Then send this update result to every node in the system. Therefore, every node in the entire system has exactly the same ledger.

We call this accounting method blockchain technology or distributed ledger technology.

Then the question arises, is the content of this ledger safe?

First of all, the rights of each node are the same. The destruction of any node will not affect the security of the entire system, nor will it cause data loss. Moreover, the ledger data of each node is exactly the same, which means that data tampering by a single node is meaningless. Because if the system finds that the two ledgers do not match, it will think that the version with a relatively large number of nodes with the same ledger is the real data version.

To put it simply, we all have WeChat groups, and the chat records of WeChat groups cannot be tampered with.

There are 500 people in a WeChat group, and everyone has a complete backup of the chat history on their mobile phones. It is impossible for any group member to modify the chat history on other people’s mobile phones.If you record, you can only modify your own. Even Ma Huateng cannot modify the chat history of other people's mobile phones. Even if anyone modifies his own record, other group members can correct him. As long as more group members come up with evidence, it can be proven that this person with evil intentions has modified the record.

The blockchain also stores some specific "chat records", which have unique names in the blockchain world - transactions.

The principle is the same as the WeChat group. All people who play on this blockchain (called node wallets) keep a complete transaction history. In this way, if any individual wants to modify these historical records, others can take out their own backup to prove that these malicious people are trying to cheat, and the system will automatically discard this part of the account book that is considered to have been tampered with.

3. Encyclopedia: How to understand the immutability of blockchain

Blockchain technology is also called distributed ledger technology.

In the blockchain, since everyone (computer) has exactly the same ledger, and everyone (computer) has completely equal rights, there will be no loss of contact due to a single person (computer) Or crash, causing the entire system to collapse.

Since there are exactly the same ledgers, it means that all data is open and transparent, and everyone can see the digital changes in each account.

Its very interesting feature is that the data in it cannot be tampered with. Because the system will automatically compare, it will consider the account books with the largest number of the same number as the real account books, and the small number of account books with different numbers as others are false account books.

In this case, it makes no sense for anyone to tamper with their own ledger, because unless you can tamper with most of the nodes in the entire system.

If the entire system has only five or ten nodes, it may be easy to do, but if there are tens of thousands or even hundreds of thousands of nodes, and they are distributed in any corner of the Internet, unless someone Can control most of the computers in the world, otherwise it would be impossible to tamper with such a large blockchain

4. Why can the blockchain be immutable

Blockchain is a The core of the distributed ledger database is the essence of trust, that is, the ledger is still used. There are records in the ledger that cannot be tampered with. To make it impossible to tamper with, its design is different from the traditional ledger in two points:
A signature is added to each record
Every device in the blockchain network maintains a complete and identical ledger
Another feature of the blockchain is this general ledger A copy is kept in each computer, and each copy is exactly the same, which ensures that one ledger is destroyed (disk damage)Or it has been tampered with and rendered unavailable), the ledger on other machines can still be used, ensuring that data will not be lost.
The above two points are the core technologies that enable blockchain to establish a trust relationship. It ensures that the data is reliable and cannot be tampered with. This revolutionary feature enables trust transfer between two strangers without the need for an intermediary agency. With participation, with this foundation, the entire "new institutional economics" will cease to exist, and even the trust companies derived from it will be replaced. This is probably why Alipay announced the introduction of blockchain in January 2017. For technical reasons, I boldly predict that all Internet companies in the future will be built on the blockchain. It is conceivable that there are property rights chains, food safety chains, financial services chains, blockchain chains, etc.
The application fields of blockchain include digital currency, certificates, finance, anti-counterfeiting and traceability, privacy protection, supply chain, entertainment, etc. With the popularity of blockchain and Bitcoin, many related top domain names have been registered. , which has had a relatively large impact on the domain name industry.

5. The key to the non-tamperability of the blockchain is

Each block header of the blockchain is encapsulated with the hash code of the previous block. This mechanism ensures that the block The technical characteristics of blockchain data that cannot be tampered with.
Blockchain is the current development trend of the technology industry. "Decentralization" and "non-tampering" are the technical advantages that ordinary people can blurt out. “Decentralization” is well understood as a non-centralized and unorganized action. However, judging from the current development, the application of blockchain technology is still relatively weak and multi-center.

6. Why the blockchain cannot be tampered with and analyze its basic principles

What is the working principle of the blockchain that cannot be tampered with? To understand this, we need to introduce a concept: hash algorithm. There are many types of hash algorithms, and their basic function is to convert a data file of any length into a unique corresponding fixed-length string.

You can understand that any file will generate a string of fixed-length garbled tags.

This algorithm is irreversible, that is, when you get the label, you cannot reversely deduce the original data file.

If there are subtle changes in the data file, such as adding a punctuation mark, then after re-hashing, the new tags will be very different from the original tags.

It is impossible to infer what happened to the data file from the difference between the old and new tags. Therefore, it is easy to verify whether a certain file existed at a certain moment, or whether two files are the same.

It is this irreversibility that determines the irreversibility of the blockchain. In each block, in addition to the transfer transaction data within ten minutes, there is also a block header.

The header contains the hash of the previous block's data. These hashes are nested layer by layer with a fixed length, and finally all blocks are concatenated to form a blockchain. The blockchain contains all transactions and new currency issuances that have occurred since the inception of the chain.OK.

If I were a bad person, I would tamper with the agreement. Include the sender and receiver of the transaction and the amount transferred. A sender can send Bitcoins all the way back to the earliest newly issued block of the currency.

The legitimacy of the sender's possession of these Bitcoins is guaranteed by the currency's original issuance block record and all historical transaction records related to the currency.

Therefore, tampering with one transaction means that all subsequent hashes and related transaction records will have to be tampered with again. This requires extremely high computing power and difficulty, and the probability of success is zero.

7. Functional characteristics of blockchain technology

Blockchain is essentially a distributed storage system. Because it adopts a transaction accounting storage model, It can also be called a distributed accounting system. Beijing Muqi Mobile Technology Co., Ltd., a professional blockchain development company, welcomes exchanges and cooperation. Let’s talk about the functional characteristics of blockchain technology.

In traditional platform technology, central decision-making is a very common data processing method. For example, in the traditional bank transfer method, transaction information must be processed by the bank's central server cluster, and the transaction information is processed through the layers of the bank's central server cluster. The data upload and instruction distribution complete the transaction between the two accounts. Every transaction in the blockchain is directly communicated and transacted by both parties. From the initiation of the transaction to the confirmation of transaction completion, all nodes are equal and have exactly the same permissions without going through any intermediaries. This kind of The peer-to-peer transaction model in the network makes blockchain applications free from the risks of intermediary transactions.

It should be noted that although blockchain is often called a distributed ledger, and is even essentially a distributed storage system, blockchain is different from conventional distributed systems. The distributed structure is even more special. Distribution is a concept corresponding to centralization. All sub-nodes in the centralized structure only interact with the central node and have no connection with each other. Therefore, the central node needs to bear all the load. A centralized system Efficiency is basically only related to the processing speed of the central node. At the same time, once the central node encounters problems such as blocking, deadlock, and downtime, the entire centralized system will stagnate or even collapse directly. The characteristic of the distributed structure is that there are multiple nodes that can interact with other nodes for data. Distributed network storage technology stores data dispersedly on multiple independent machines and devices. This sounds a bit confusing, but it is easy to understand if it is classified and described based on the characteristics of centralization. The distributed structure includes multi-centralized structure and decentralized structure.

A polycentralized system refers to a system composed of multiple centralized systems, each of which includes a master node and several slave nodes. When performing task processing, the master node decomposes the task into multiple sub-tasks and sends them to multiple subordinate slave nodes for simultaneous processing. The slave node returns the processing results toAfter being transmitted to the main node, the main node will integrate the processing results of each sub-task and finally complete the task. Of course, this is just a simplified description of task processing. A multi-centralized system may have a multi-layer master-slave structure, forming a tree-like task allocation structure. At the same time, slave nodes may also take orders from multiple master nodes to maximize efficiency based on complex task management mechanisms. But the fundamental difference between multi-centralization and decentralization is whether there is a central node that controls the operation of each master node. If the top-most node is multiple nodes, then it is decentralized. On the contrary, if there is only one node at the top, it is decentralized. It's multi-centered.

In decentralization, there is a more special structure that does not have any center, which can be called a completely decentralized structure. This is also a point-to-point network structure. This structure is This is reflected in the Bitcoin network. The relative advantages of point-to-point network structure are high fault tolerance, strong node scalability, strong privacy and data consistency, etc. However, there are also problems such as redundant communication and message delay.

Figure 5 Schematic diagram of network structure division

The "decentralization" emphasized in the general blockchain field mostly refers to the ownership level of the system. The system is decentralized if it belongs to the community and all accounts, and the system is centralized if it belongs to an institution or even an individual. Decentralization is a common feature of blockchain, but the completely decentralized structure of peer-to-peer networks has few current applications. Only public chains such as Bitcoin and Ethereum belong to this structure, because anyone in the world can Enter the system at any time to read data, send confirmable transactions, and compete for accounting activities, which results in the inability to guarantee its security and system efficiency. Private chains often have one or more centers that control the nodes, and all operations require permission from the center and are subject to its constraints and restrictions. Although it uses a decentralized mechanism for routine data processing, it is strictly A distributed blockchain deployment model. The alliance chain can be regarded as a collection of private chains, which is a compromise between the security and efficiency of the public chain. It adopts a multi-center technical architecture.

Due to the natural characteristics of the blockchain that cannot be tampered with, it is based on the consensus algorithm to ensure data consistency. No node in the system can tamper with or forge transactions. All transaction contents are certain and undisputed. There will be no credit risk in transactions, and the blockchain system will also have trustless characteristics.

Based on the changes in the content carried in the block from transactions to smart contracts, the trustlessness of the blockchain has two stages. The first stage is to verify the authenticity of historical transaction behaviors in the blockchain network. Trust, the second stage is trust in future transaction behavior based on smart contract rules.

The first stage of trust in the authenticity of historical behaviors can be simply understood as the blockchain system eliminates the process of proving historical transactions. When we tell someone that something happened,Evidence is needed to convince others, and this evidence often requires a credible third party to prove it and provide credit guarantee through verification. For example, the electronic transaction slip provided by the shopping platform is evidence when shopping online, the tax bureau invoice provided by the restaurant when dining out is evidence, or the marriage certificate provided by the institution when purchasing a house using the identity of a couple is evidence. The person who accepts this information also needs to verify the evidence to be sure that these things have indeed happened. Corresponding to the previous article, when an online shopping dispute occurs, it is necessary to check whether the electronic transaction slip of the shopping platform actually exists; When reimbursing expenses, the signature of the invoice needs to be verified; when confirming the identity of two people as a couple, the anti-counterfeiting mark of the marriage certificate needs to be verified. However, the data in the blockchain system is considered to be non-tamperable and non-forgery. Therefore, as long as you explain a historical event to other nodes on the chain, you do not need any third-party certification, because the information on the data block can be obtained at any time. Come out and verify it directly, which results in the distrust of historical transactions in the blockchain.

The second stage is trust in future transaction behavior, because in an ideal state, the smart contract of the blockchain is bound to the business, that is, the smart contract has mandatory execution in the blockchain system. force. Because the smart code is completely public and is recorded in the main chain and stored by all accounts. After the smart contract is called or triggered by a certain mechanism, the transaction will be enforced and there is no possibility of denial. Therefore, users in the blockchain system do not have to worry about the other party's credit risk in the future, and there is a lack of trust in future transactions.

In the public chain, the ledger of each node completely records all transactions. The blockchain does not directly record real-time account information, but obtains real-time account information through transaction traceability. At the same time, since anyone can create a blockchain account to form a blockchain node, the information in the public chain can be considered open to everyone, which forms the open and traceable characteristics of the blockchain. And because the code of the public chain is often open source, what is open and traceable is not only the transaction data in the system, but also the transaction rules of the entire system. The high degree of openness and transparency enables the blockchain to meet many application scenarios that require open data. .

However, the blockchain has developed many variants based on the Bitcoin network, such as light nodes, private chains and consortium chains. These variants cannot meet the strict requirements of openness. Traceable. Light nodes can only execute and verify transactions, and do not have all transaction data for traceability, so light nodes do not have traceability. However, this problem only lies in the user's choice. If there is a good enough hardware environment, the user can choose to become a full node instead of a light node in order to master all data. In addition, access permission or verification is required to join a private chain or alliance chain, and read permissions are selectively open to the outside world and are not open to the entire network, which does not meet the strict sense of openness.

8. The technical characteristics of blockchain include: (). a Decentralization b Traceability c Openness and transparency d Non-tampering

The technical characteristics of blockchain include decentralization, non-tampering, consensus trust mechanism, openness, anonymity, cross-platform, etc.

6. Cross-platform

Similar to the TCP/IP protocol of the Internet, blockchain can also be regarded as a basic communication protocol. The cooperation of other mechanisms together constitutes the value Internet based on blockchain. Nodes on the blockchain network operate independently based on common algorithms and data structures. They mainly consume computing resources and have nothing to do with the platform. Computing nodes can be deployed on any platform.

It can be said that the characteristics and development of blockchain come from the soil where it was born - the development of Internet technology and the rise of cloud computing and big data.