The risk of blockchain system
the centralized trading platform covers the whole trading process including account opening, recharge, automatic transfer and transaction withdrawal. That is to say, when we put our digital assets into the address of the trading platform, the trading platform becomes the trustee of our digital assets, and the control of the actual assets is in the hands of the trading platform
different from the centralized trading platform, the decentralized platform does not need to register an account. It only needs to undertake the responsibilities of asset custody, matching transaction and asset clearing, and does not need to provide non trading function, account system, kcy and legal currency exchange functions like the centralized exchange; On the other hand, in the decentralized trading platform, all operations are realized through smart contracts, and this transaction needs to wait for the confirmation of the blockchain before it is successfully completed
based on the above attributes, the decentralized platform avoids the moral hazard of the trading platform and the centralized attack of hackers to a certain extent. However, in this trading mode, the security of assets depends on the users themselves.
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
facing the use of voltage generally 480 V, although one installation uses 4160 V, shielded cable end. Many textile mills and processing plants use 480 V distribution, with 2300 fifth very large delta often connected, so that plant action may continue, even if a stage becomes grounded, but these systems are equipped with ground display lights, and usually have special fault tracking equipment, so that the first stage to ground fault can be detected and isolated
other plants use a solidly grounded or resistor grounded circuit to trip with a selective earth fault. Heavy copper chains extend from the construction of steel frames, each motor providing grounding in most plants. In addition, the 480 V line is usually run on a metal conctor, which is often used as an additional ground conctor, which is ultimately bonded to the substation ground bed. Conctor ground command can be good for low resistance paths, if continuity is guaranteed in each union and flex coupling vibration, if not a problem. However, in some installations using shake head screen size separation, especially in sand and gravel or dredge plants, vibration may be so severe that the wire can literally be unshakable into pieces. In these cases, the conctor did not make enough frame grounding conctors
most surface mine visits also utilize resistance grounded system circuits to feed portable and mobile devices powered by trailing cables. However, at least one facility uses a floating delta secondary if there is no grounding conctor. Theoretically, the ground fault current cannot flow in a delta system, but in reality it does because of the stray capacitance circuit. In addition, if two nearby devices have progressively failed to frame at different stages, a person who involves both machines at the same time will be shocked with a full range of line to line voltages. Ungrounded systems pose a significant risk to personnel unless they are equipped with a very sensitive GFI type trip, which is not available except for 120 volt circuits. All rake access utilizes shielded trailing cables, and their power system is equipped with resistance
Blockchain technology exchange
when blockchain technology is generally regarded as a technology in the market, the blockchain team of ant financial services technology laboratory gave a calm explanation: blockchain technology itself is not a special technology, but is integrated by many previous technologies, such as P2P network, many nodes, cryptography, It also includes something similar to consensus. So from this point of view, if we only use the previous technology, we will graally form the blockchain technology in the end