1. On the Internet, the most typical example of centralization is the portal website. By collecting all the information on the Internet on its own platform, the portal website forms a central node, and then extends many branches from this node. Generally speaking, only one node is making decisions. According to the analysis of jinwowo network technology, the characteristics leading to centralization are as follows:
1. The central node grasps the information of distributed nodes
2. The sub nodes do not master the information of other nodes (centralization, non-public transactions)
moreover, the pain point of centralization is that the security of the system depends on the security of the central node, and the distributed node has no control over it.
2. virtual currency and electronic currency are not the same concept
the definition of e-money is to convert a certain amount of cash or deposit from the issuer and obtain data representing the same amount. By using some electronic methods, the data can be directly transferred to the payment object, so as to pay off the debt. E-money means that consumers pay traditional money to issuers of e-money, and issuers store legal money of equal value with traditional money in electronic devices held by consumers
electronic currency is the electronization of the legal tender, including our common bank cards, Internet banking, electronic cash, etc., as well as the third party payment developed in recent years, such as Alipay, fortune paid and so on. No matter what form these electronic currencies are and through which institutions they circulate, their original source is the legal money issued by the central bank
but virtual currency is the electronization of illegal currency, and its original issuer is not the central bank. For example, Tencent Q currency and other game currency, such virtual currency is mainly limited to circulation in a specific virtual environment. After the emergence of bitcoin, through the blockchain technology to better solve the problem of decentralization, distrust, to achieve global circulation, is sought after in the world. Electronic currency and virtual currency are collectively referred to as digital currency
3. Yes, the current deception is not surprising. In short, you should be more careful
with the rapid development of mobile communication, online dating has become a widespread form of communication, but there are some sweet traps set by outlaws. How to avoid being cheated in the complicated virtual space, so as to avoid unnecessary property losses
for example, he said that in his uncle's home in Taiwan, he sent a table of food, enlarged the picture, and you can see the logo of the drink, which is obviously a mainland brand, which needs to be seen carefully
4. 1. Medical
in the medical field, data sharing between hospitals and micro v-bq-y means more accurate diagnosis, more effective treatment, and can promote the overall service ability of the medical system. However, data sharing also means the problem of doctor-patient privacy exposure. Blockchain technology allows hospitals, patients and all parties in the medical interest chain to share data in the blockchain network without worrying about the security and integrity of the data
2. Logistics
at present, the most critical problems of logistics are missing and damaged express. Blockchain technology can record all links in the process from delivery to acceptance of goods, and directly locate the problems in the intermediate links of express delivery through network consensus, so as to ensure the traceability of information, so as to avoid the occurrence of problems such as warehouse explosion, package loss, wrong picking and wrong picking
3, big data
big data is an indispensable link in the development of modern enterprises, and the security and non tamperability of blockchain can liberate more data security. Based on the consensus of the whole network, the data reliable blockchain data, which is the basis of micro v-bq, is tamperable and safe, and makes the quality of data obtain unprecedented strong trust endorsement, and also makes the development of database enter a new era
4. Distributed business platform
combined with the advantages of decentralized blockchain technology and distributed account book, there are many integration points worthy of attention in the field of this technology and business platform. If we can take blockchain technology as the core support technology, research and develop the transaction mode and transaction system based on blockchain technology in the field of commodity trading, and trade directly, in this way, Procers can get more benefits and consumers can get lower proct costs
Generally speaking, blockchain system consists of data layer, network layer, consensus layer, incentive layer, contract layer and application layer
among them, the data layer encapsulates the underlying data blocks and related basic data and algorithms such as data encryption and timestamp
The
network layer includes distributed networking mechanism, data transmission mechanism and data verification mechanism; The consensus layer mainly encapsulates all kinds of consensus algorithms of network nodes
the incentive layer integrates economic factors into the blockchain technology system, mainly including the issuing mechanism and distribution mechanism of economic incentives
the contract layer mainly encapsulates all kinds of scripts, algorithms and smart contracts, which is the basis of the programmable characteristics of blockchain
The
application layer encapsulates various application scenarios and cases of blockchain
in this model, chain block structure based on timestamp, consensus mechanism of distributed nodes, economic incentive based on consensus computing power and flexible and programmable smart contract are the most representative innovations of blockchain technology
5. 1. CT means telecommunication
communication technology (abbreviated as CT), also known as communication engineering (also known as information engineering, telecommunication engineering, formerly known as long-distance communication engineering, weak current engineering), is an important branch of electronic engineering, but also one of the basic disciplines
It means informatization
Information Technology (abbreviated as it) is the general term of various technologies mainly used for managing and processing information. It mainly applies computer science and communication technology to design, develop, install and implement information system and application software. It is also often referred to as information and communication technology. It mainly includes sensing technology, computer and intelligence technology, communication technology and control technology
extended data
People's definition of information technology varies with its purpose, scope and level:
1. Any technology that can expand people's information function can be called information technology
Information technology includes communication, computer and computer language, computer games, electronic technology, optical fiber technology, etc Modern information technology is characterized by computer technology, microelectronics technology and communication technology Information technology refers to the general term of the methods and equipment used to acquire, process, store, transform, display and transmit text, numerical value, image and sound information, including providing equipment and information services, supported by computer and communication technology Information technology is a purposeful combination of the experience, knowledge and skills accumulated by human beings in the process of understanding and transforming nature in the struggle of proction and scientific experiments, such as acquiring information, transmitting information, storing information, processing information and standardizing information, and the labor materials embodying these experiences, knowledge and skills Information technology is the general term of the relevant methods, means and operating proceres for the management, development and utilization of information resources Information technology refers to a kind of technology that can expand the function of human information organs Information technology refers to the training methods and management skills of science, technology and engineering applied in information processing and processing; The application of the above methods and techniques; Computers and their interactions with people and computers, and the social, economic and cultural things corresponding to people. " Information technology includes all aspects in the process of information transmission, such as information generation, collection, exchange, storage, transmission, display, identification, extraction, control, processing and utilization Information technology is a technology that studies how to obtain, process, transmit and use information
6. With the development of blockchain today, it has already extended from the initial financial transactions to all application projects that need to be guaranteed or certified by intermediaries, such as housing transactions, automobile trading, etc. it can even integrate blockchain technology with other application services through the series connection of API, so as to accelerate the generation of various innovative applications, It even helps to accelerate the development of Internet of animals applications
the earliest application of blockchain is bitcoin. Blockchain is a series of data blocks generated by using cryptographic methods. It is like a database ledger, and the ledger also contains all transaction records since bitcoin, including multiple block records. Each block corresponds to a part of the transaction, and records the hash value of the previous block, Form a chain like data structure
many experts believe that the emergence of blockchain technology solves the missing link in the security, privacy and reliability of the Internet of things. It can be used to track billions of interconnected devices, facilitate transactions and collaborative processing between devices, and save a lot of costs for the Internet of things instry. This decentralized method will eliminate single point of failure and create a more reliable device operation ecosystem. At the same time, the encryption algorithm used by the blockchain can also bring higher privacy for consumer data
the advantage of blockchain is that it is open, and every network participant can see the block and the transaction information stored in it. However, this does not mean that everyone can see your actual transaction content, which is protected by your private key
blockchain is decentralized. Therefore, no single institution can approve the transaction or set special rules for the reception of the transaction, which means that there is a huge trust between the participants, so all the network participants must reach a consensus to receive the transaction
more importantly, the blockchain is very secure, this kind of data can only be continuously expanded, and the previous records cannot be changed. Moreover, the ledger used by blockchain is tamper proof and cannot be manipulated by lawless elements. This ledger is not located in a specific location and cannot attack middlemen, because no single communication thread can be intercepted
blockchain can be applied to the Internet of things to ensure information security, such as manufacturers of equipment and instruments. With the help of blockchain technology, we can trace the manufacturer, proction date, batch number and other information of the manufacturing process of each component, so as to ensure the transparency and plasticity of the whole proction process and effectively improve the availability of the whole system and components, Then ensure the safety of equipment operation
the unique consensus mechanism of blockchain is to connect the devices through the point-to-point way, rather than through the central processor. The consensus between the devices is maintained without central verification, which ensures that when a node has problems, the overall data security of the network will not be affected
now, with the continuous development and warming of blockchain technology, Shenzhen Beihang IOT Research Institute www.buaaiot.org I think it will also change and integrate into various instries in its own unique way. The birth of blockchain technology makes all kinds of algorithms more efficient. Its decentralized principle and distributed computing rules enable all things to connect and calculate in seconds, and prevent hackers from attacking data. All kinds of assets can be registered and traded on the block, and the data can never be tampered with and irreversible. This intangible Charm makes all kinds of assets converge on the block
7. Introction: Black Pai is a technology company dedicated to the research and development of the underlying technology of the next generation blockchain, focusing on the construction of value network and providing tools and platforms for decentralized cooperation. At present, heipai technology is developing three major projects: decentralized digital currency trading tool "coin stack", the bottom public chain valuecyber in the era of blockchain 3.0, and many "blockchain +" applications
legal representative: Zhang Jie
time of establishment: June 23, 2016
registered capital: RMB 1 million
Business Registration No.: 110113021537102
enterprise type: limited liability company (invested or controlled by natural person)
address: 2-07, building 6, ronghuiyuan, airport economic core area, Shunyi District, Beijing
8. WLAN is considered to be an inexorable network. In addition to strengthening network management, it also needs the construction, implementation, maintenance and management of test equipment. Although the winter of it has not yet passed, WLAN has won the favor of many companies, governments, indivials and telecom operators for its convenient installation, use, high-speed access and mobile access. But in WLAN, because the data transmitted is radiated in the air by radio waves, the radio waves can penetrate the ceiling, floor and wall, and the transmitted data may reach the reception equipment that is not expected, installed on different floors, or even outside the building where the transmitter is located, the data security has become the most important problem. The first problem is that it is easy to intrude into the WLAN, and it is very easy to be found. In order to enable users to discover the existence of the wireless network, the network must send beacon frames with specific parameters, so as to provide the attacker with the necessary network information. The intruder can attack the network from the side of the road, buildings and any other place through the high sensitive antenna without any physical invasion. Solution: strengthen network access control, easy access does not mean easy to attack. An extreme means is to prevent the leakage of electromagnetic waves through the electromagnetic shielding of the house. Of course, the risk of wireless network configuration can be reced through strong network access control. If the AP is placed outside the network security equipment such as firewall, it is better to consider connecting to the backbone network through VPN technology, and the better way is to use the new wireless network procts based on IEEE802.1x. IEEE802.1x defines a new frame type of user level authentication. With the help of the existing user database in the enterprise network, the front-end authentication based on IEEE802.1x wireless network is converted to the back-end authentication based on rasius wired network. The second problem is that the illegal AP WLAN is easy to access and configure, which makes network administrators and security officials have a headache. Because anyone's computer can be connected to the network through their own AP without authorization. Many departments build their own WLAN without the authorization of the company's it center. Users access the network through illegal AP, which brings great security risks to the network. Solution: regular site review, like many other networks, wireless networks also have corresponding requirements in terms of security management. Before the intruder uses the network, he can find the unauthorized network through the receiving antenna. The monitoring of physical sites should be carried out as frequently as possible. Frequent monitoring can increase the probability of finding the illegal configuration sites, but it will take a lot of time and the mobility is poor. A compromise is to choose small hand-held testing equipment. The administrator can go to any location of the network at any time through the handheld scanning device for detection. The third problem is that more than half of the users who use the service without authorization only make few modifications on the basis of their default configuration when using AP. Almost all APS use the default configuration to open WEP for encryption or use the default key provided by the original factory. Due to the open access mode of WLAN, unauthorized use of network resources will not only increase the cost of bandwidth, but also lead to legal disputes. Moreover, if unauthorized users do not comply with the service terms proposed by the service provider, ISP may interrupt service. Solution: the best defense method to strengthen security authentication is to prevent unauthorized users from entering the network. Because the access privilege is based on the user's identity, encrypting the authentication process by encryption is the premise of authentication, and VPN technology can effectively protect the network traffic transmitted by radio waves. Once the network is successfully configured, strict authentication methods and authentication policies will be crucial. In addition, we also need to test the wireless network regularly to ensure that the network equipment uses the security authentication mechanism, and ensure that the network equipment configuration is normal. Due to the limitation of service and performance, the transmission bandwidth of WLAN is limited. Due to the cost of physical layer, the actual maximum effective throughput of WLAN is only half of the standard, and the bandwidth is shared by all users of AP. Wireless bandwidth can be engulfed in several ways: network traffic from wired network far exceeds wireless network bandwidth. If attackers send a large amount of Ping traffic from fast Ethernet, they will easily engulf AP's limited bandwidth; If broadcast traffic is sent, multiple APS will be blocked at the same time; The attacker can send signals in the same wireless channel as the wireless network, so that the attacked network will automatically adapt through CSMA / Ca mechanism, which also affects the transmission of wireless network; In addition, the transmission of large data files or complex client / server system will proce a lot of network traffic. Solution: network detection and location performance failure should start from monitoring and finding problems. Many AP can report statistical information through SNMP, but the information is very limited, which can not reflect the actual problems of users. The wireless network tester can truly reflect the current position signal quality and network health. The tester can effectively identify the type of network rate and frame, and help to locate the fault. Problem 5 address spoofing and session interception because 802.11 WLAN does not authenticate data frames, attackers can redirect data streams and confuse ARP tables by spoofing frames. In a very simple way, attackers can easily obtain MAC addresses of sites in the network, which can be used in malicious attacks. In addition to spoofing frames, attackers can also detect authentication defects in AP by intercepting session frames and detect the existence of AP by monitoring broadcast frames sent by AP. However, since 802.11 does not require an AP to prove that it is an AP, it is easy for an attacker to enter the network as an AP. Through such an AP, the attacker can further obtain authentication information and enter the network. Before 802.11i is used to authenticate every 802.11mac frame, network intrusion through session interception is inevitable. Solution: isolate from important networks before 802.11i is officially approved, the threat of MAC address spoofing to wireless networks still exists. Network administrators must disconnect the wireless network from the vulnerable core network. Problem 6: traffic analysis and traffic interception 802.11 can't prevent attackers from passively monitoring network traffic, and any wireless network analyzer can intercept unencrypted network traffic without any hindrance. At present, WEP has a vulnerability that can be exploited by attackers. It can only protect the initial data of user and network communication, and the management and control frames can not be encrypted and authenticated by WEP, which provides an opportunity for attackers to terminate network communication with deceptive frames. In the early days, WEP was very easy to be decrypted by tools such as airsnort and wepcrack, but later many manufacturers released firmware to avoid these known attacks. As an extension of the protection function, the protection function of the latest WLAN procts is further improved. Using the key management protocol, the WEP key can be changed every 15 minutes. Even the busiest network will not generate enough data in such a short time to confirm that the attacker has broken the key. Solution: use * protocol for encryption. If the user's wireless network is used to transmit more sensitive data, it is not enough to use WEP encryption only. It is necessary to further use encryption technologies such as SSH, SSL and IPSec to enhance the security of data. Problem 7 advanced intrusion once the attacker enters the wireless network, it will become the starting point for further intrusion into other systems. Many networks have a set of carefully designed security devices as the shell of the network to prevent illegal attacks, but the network protected by the shell is very vulnerable to attack. Wireless network can quickly access the network backbone through simple configuration, but this will expose the network to attackers. Even if there are some border security devices in the network, the network will also be exposed and attacked. Solution: isolate the wireless network from the core network. Because the wireless network is very vulnerable to attack, it is considered as an inexorable network. Many companies arrange wireless networks in public areas such as lounges and training classrooms, as a way to provide customers with access. The network should be arranged outside the protective shell of the core network, such as the firewall, and VPN should be used to access the core network. WLAN security Author: unknown update time: March 20, 2005 foreword even if the system manager of WLAN uses the built-in secure communication protocol: WEP (Wired Equivalent Privacy), the security protection of WLAN is still insufficient. A seven month long survey in London showed that 94% of wireless LANs were not set up correctly to stop hackers. Cybercrime unit, which is affiliated to the International Chamber of Commerce, has found that even if wireless networks are secure, they will be greatly discounted for various reasons. Nowadays, "drive by hacking" is very popular. Hackers drive into the public business district and infiltrate the WLAN of enterprises directly in the car where the signal reaches Three researchers, Nikita Borisov, Ian Goldberg, and dabid Wagner, from Berkeley University in California, discovered a major flaw in WEP coding last year; In addition, in August 2001, cryptographers Scott fluhrer, itsik mantin and adishamir pointed out the shortcomings of RC4 coding, which is the basis of WEP. Just a few days later, at the end of August 2001, Rice University Students and two at & T lab employees (Adam Stubblefield and John joannidis, avield D. Rubin) translated the contents of these two papers into actual program code. Surprisingly, there is no special device involved. As long as you have a personal computer that can connect to the wireless network, you can download the updated driver from the network, and then you can start to record all packets on the network, and then decode them. In many wireless LANs, WEP key is described as a word or bit string, which is used to authenticate the whole network. At present, WEP uses two encoding sizes, 64 and 128 bits, including 24 bit initial vector (IV) and actual secret key value (40 and 104 bits). The familiar 40 bit coding mode is actually equivalent to 64 bit coding. The management of key value is not considered in this standard; The only requirement is that the wireless network card and base station must use the same algorithm. Usually, every user in LAN will use the same encryption key; However, LAN users will use different IV to avoid RC4 content generated "randomly" by packets always using the same WEP key value. Before the packet is sent out, it will go through an "integrity check" and generate a verification code. Its function is to prevent the data from being tampered by hackers in the process of transmission. RC4 will then generate a keystream from the secret key value and IV, and then use this keystream to perform XOR (exclusive or) on the data and IC. First of all, IV will be sent out in normal text mode, but
