What are the blockchain attacks

1.

Although driven by the influx of capital and talents, the blockchain instry ushered in rapid development, but as an emerging instry, the frequent warning of its security vulnerabilities caused people to worry about the risk of blockchain

Yu Kequn, director of the national information technology security research center, pointed out that the emergence of blockchain has brought people a lot of expectations for privacy exposure, data leakage, information tampering, network fraud and other issues. However, there are still many challenges in the security of blockchain

Li Bin, assistant director of China Information Security Evaluation Center, analyzed that the current blockchain is divided into three types: public chain, private chain and alliance chain. No matter which type, it faces security challenges in algorithm, protocol, use, time limit and system. What is particularly critical is that the current blockchain is still facing 51% attack problem, that is, nodes can successfully tamper and forge blockchain data by mastering more than 51% of the network examples

it is worth noting that in addition to external malicious attack risk, blockchain also faces the threat of its endogenous risk. Yu Kequn reminded that how to build a complete security application system around the equipment, data, application, encryption, authentication and authority of the application system of the whole blockchain is an important problem that all parties must face

Wu Jia also analyzed that as an emerging instry, employees in the blockchain instry are lack of safety awareness, which leads to the low safety factor of the software and hardware related to the blockchain and a large number of security loopholes. In addition, there are many ecological links in the whole blockchain. In contrast, the strength of the relevant security employees is scattered and it is difficult to form a joint force to solve the problem. A systematic solution is needed to meet the above challenges

content source: zhongxin.com

2. Blockchain features: 1. Security: not attacked by any person or entity; 2. No information can be tampered with; 3. Traceable, all nodes in the network can access; 4. Decentralization, no third party. About blockchain messages, you can learn about it in cryptography.

3. Both indivials and enterprises can purchase alicloud servers and develop an app. However, real name authentication is required. Personal real name certification and enterprise real name certification, after passing the certification, you can easily choose cloud computing procts. Leave a message or see the content of the blog, Lao Wei has written many detailed articles, which can help you get started.

4. In a simple explanation, 51% attack is also called majority attack. It means that malicious miners control more than 50% of the hash rate of the blockchain network, and then attack the network and take over the blockchain network, so that criminals can reverse transactions, stop payment or prevent new transactions from being confirmed
for more information about 51% attacks, you can learn about them on the password finance network,

5. Blockchain technology has three obvious characteristics: openness, security and uniqueness
openness mainly refers to that the stored information in the blockchain is completely open to all participants. This is mainly determined by the point-to-point network storage mode of the blockchain. In the blockchain network, each node can store a of the blockchain, and the uniqueness of the blockchain can ensure that the is exactly the same between different nodes
security mainly refers to that the information stored in the blockchain block is saved after being processed by digital encryption technology, and only the private key holder can decrypt the information to obtain the real information. Other members can only see and verify the integrity and uniqueness of information, but cannot see the real information
uniqueness is mainly e to the fact that the information on the blockchain cannot be tampered with once it is on the chain, so it is unique. Of course, the uniqueness here also includes the uniqueness in space, that is, all nodes have only one version of information, and also includes the uniqueness in time, that is, the historical data cannot be changed. This uniqueness also means that the blockchain maintains the characteristics of a unique main chain in the process of operation, and once other chains appear, it is a bifurcation. The emergence of bifurcation will lead to the plication of blockchain in two different spatial dimensions. Of course, to solve this problem, we need to set reasonable consensus rules to avoid. When the concept of blockchain was hot, many related top domain names were registered and used as blockchain platforms.

6. How to protect my bitcoin after bifurcation
if bitcoin really forks, as an ordinary user, the biggest risk is replay attack
what is replay attack? If bitcoin is split into one or more bitcoins, such as btc1 / btc2 / btc3, each bitcoin account will have a corresponding number of all bifurcated coins according to its bitcoin balance
because the address, private key, algorithm, etc. on each chain are the same, and the transaction format is also the same, the transaction initiated on one blockchain can be broadcast on another blockchain and may be confirmed. This is the "replay attack."
in short, when you transfer btc1, your btc2 / btc3 may also be transferred at the same time
however, at present, many forked coins have done two-way anti replay attack processing to avoid the risk of replay attack after forking.

7. Heteromorphic attack, also known as address pool pollution, refers to the intrusion and pollution of nodes between similar blockchain systems. This is an attack that most public chains are likely to face. The opportunity of this attack is that many public chains have handshake protocols with similar chains, and then the system can not identify whether the node belongs to its own chain. The attacker can use this point to collect the address of the public chain and make a malicious handshake, contaminate the address pool through the node handshake, so that the nodes of different chains shake hands with each other and push the known nodes in their respective address pools to each other, causing more nodes to contaminate each other and eventually spread to the whole network. The communication performance of the node under heteromorphic attack will decline, and the node will be blocked, which will eventually lead to the abnormality of the main network. The security of blockchain system is not only provided by technology itself, but also provided by developers. The more careful the program logic designed by developers, the lower the possibility of being broken. Therefore, if you need to develop a system, you must find a reliable development company. Xuanling technology is a reliable blockchain development company. Their strength and experience in blockchain development are trustworthy. If you have any intention, you can consult their company.

8. The result of these two attacks is that the other party's system is out of service or crashed e to information overload. But DoS attack is a single server attack, while DDoS attack is distributed multiple servers attack, the success of the attack is higher. The application of blockchain technology should be more and more, so it is necessary to understand the knowledge of blockchain. It is recommended that you go to the official website of Xuanling technology. This website has many popular science and application posts of blockchain technology, which should be of great help to blockchain learning.

9. Replay is also called replay. As the name suggests, it means that the same message or data is sent twice or more. If the receiver does not take relevant measures to continuously receive the information, it will not be able to effectively identify that the data has been received, which will bring replay vulnerability. Replay attacks mainly occur after the forking of the blockchain, because the two sides after the forking still keep the data before the forking, so the same transaction can be done on both sides after the forking, so it is difficult to distinguish whether the information has been received. Replay attack is mainly used in identity authentication, which can destroy the correctness of authentication, fish in troubled waters, enter the system and steal system data. Although blockchain is considered to be a relatively secure data storage technology at this stage, there are many ways to attack it, so it is also very important for the maintenance of the system. Xuanling technology has a lot of experience in the field of blockchain development, and they have a perfect after-sales maintenance mechanism, which can ensure the maximum security of the system.