Blockchain network security case

1. Security in blockchain comes from some attributes< Mining blocks need to use resources< Br > 2. Each block contains the hash value of the previous block< Br > imagine if the attacker wants to change the chain by changing the transaction five blocks ago. If they tamper with the block, the hash value of the block changes. Then the attacker must change the pointer from the next block to the changed block, and then change the hash value of the next block... This will continue until the end of the chain. This means that the farther the block is behind the chain, the greater the resistance to change. In fact, the attacker has to simulate the hash capability of the whole network up to the front end of the chain. However, when the attacker tries to attack, the chain continues to move forward. If the attacker's hash value is lower than the rest of the chain (< 50%), they will always chase and never proce the longest chain. Therefore, this type of blockchain can resist attacks, where the attacker's hash value is less than 50%< Br > when attackers have 51% hash value, they can rewrite the network history with a list of valid transactions. This is because they can recalculate the hash value of any block sort faster than the rest of the network, so they can ultimately guarantee a longer chain. The main danger of 51% attacks is the possibility of double spending. This simply means that an attacker can buy an item and show that they have paid with any number of confirmations on the blockchain. Once they receive the item, they can reorder the blockchain so that it doesn't include the send transaction and get a refund< Br > even if the attacker has more than 50% hash value, the attacker can only do so much damage. They can't do things like transfer money from the victim's account to their account or print more coins. This is because all transactions are recorded by the account?? Account owners sign, so even if they control the entire network, they cannot forge account signatures.

2. Because each block contains its own hash value and the hash value of the previous block, changing a hash value will invalidate the rest of the blockchain
if you have problems with blockchain, you are welcome to chat in private~~~~~

3. 1. Weizhong bank uses blockchain technology for loan clearing
in September 2016, Weizhong bank and Shanghai Huarui bank put into trial operation the inter-bank joint loan clearing platform based on alliance blockchain technology to optimize the settlement and clearing of "micro loan" joint loans of the two banks. With the introction of the blockchain system, all the information is recorded on the blockchain network, which can not be tampered with. The transaction process is cleared at the same time, realizing real-time clearing, saving a lot of manpower and material resources
2. China UnionPay uses blockchain technology to realize inter-bank points exchange
in September 2016, China UnionPay and IBM tried out a shared points system based on blockchain technology. Using this blockchain system allows users to exchange bonus points across banks and platforms. In other words, the bonus points of one bank can be exchanged for bonus points of other banks, or even multiple airline mileage and supermarket awards. It greatly improves the use efficiency of bank points
3. Toyota uses blockchain technology to track auto parts
in October 2016, Toyota joined R3 alliance to store the proction, processing and use of each part in the blockchain through blockchain technology, so that when there is a problem with auto parts, the source of the parts can be easily and quickly found
4. Central bank's blockchain digital bill trading platform
in January 2017, the central bank's blockchain based digital bill trading platform was successfully tested. The introction of digital currency for settlement can realize the synchronous transfer of capital flow and information flow of digital bill transaction, so as to realize DVP bill settlement. At the same time, the blockchain digital identity solution solves the problem of repeated KYC authentication between different financial institutions. It not only solves the problem that the transaction amount of digital bills is confidential to the unrelated parties, but also ensures that the regulatory parties such as the exchange have the mechanism of seeing through when necessary
5. Ant financial services blockchain application
in August 2017, ant financial services blockchain technology tested water insurance and helped Xinmei mutual insurance company to launch the first love rescue account in the domestic insurance instry. Blockchain technology makes every capital flow open and transparent, the data of every capital flow can not be tampered with, and the whereabouts and uses of every capital can be traced. In November of the same year, ant chain was used in food safety traceability and traceability of genuine procts. At present, the milk powder proced in Australia and New Zealand and Moutai in China, users can only know if they are genuine procts by scanning Alipay.
there are many other successful cases at home and abroad, all of which indicate that the application of blockchain technology is graally promoted, and is favored by various instries. Accompanied by the emergence of many blockchain technology companies, they want to take a share in this field. However, after the people's Bank of China and other seven ministries and commissions issued the "notice on preventing the financing risk of token issuance"), with the increasing difficulty of registration, there are more empty shell companies in the intermediary instry chain, and few companies have practical applications
in addition, the security technology of blockchain has always been concerned and controversial. Nowadays, blockchain mainly faces five security problems: the security of underlying code, cryptographic algorithm, consensus mechanism, smart contract and digital wallet.

4. Improving network security
blockchain is a decentralized and distributed electronic classified accounting method based on the model of providing absolute security and trust. Using encryption technology, transactions are recorded chronologically and publicly, and each block has a timestamp and a link to the previous block. Importantly, these digital "blocks" can only be updated through the consensus of all participants, and data interception, modification and deletion are almost impossible.

5. When it comes to the nature of blockchain, several key words are familiar. For example, decentralization, distrust, consensus mechanism, asymmetric encryption, distributed accounting, tamper proof, absolute transparency, openness and so on. At the same time, some teaching posts also list the structure of blockchain, such as data layer, network layer, consensus layer, incentive layer, contract layer and application layer
however, it's easy for people with an eye to see why there is no security layer? In fact, several key features of blockchain have already solved the security problem. First, the blockchain uses asymmetric encryption technology. In fact, encryption and decryption are different keys, namely public key and private key. In short, the public key is open to the public, while the private key is absolutely confidential
secondly, distributed bookkeeping is a way for blockchain to store data. It can also be understood as distributed storage, which is consistent with the concept of decentralization. In the form of ledger, there is no central ledger in the network, and the ledger is stored in each node. Each node is not only independent, but also can act as the central node. Therefore, the central node will not be attacked, leading to the loss of core books or data, and the whole network will not be paralyzed
moreover, tamper proof is the basic feature of blockchain. As long as the chain can not be modified, and can not be deleted. If it needs to be changed, based on the principle of transparency and openness, the whole network and all nodes need to be informed. Therefore, under the democratic mechanism, the possibility of tampering with data at will is very low. Therefore, blockchain technology is applied in various instries, such as finance, payment, traceability, games, etc., such as the network "universe", Tencent's "come together to catch the demon", and Zhongan Huanyu blockchain "Dr dragon hunt" are the safe and high-quality procts under the blockchain technology.

6. Here we need to mention that the basic system structure of blockchain includes the following
① network routing ② cryptographic algorithm ③ script system ③ consensus mechanism
the security problem of blockchain is mainly the script system completed by script system, which is an abstract concept and an extremely important function in blockchain technology, The reason why a valuable network can be formed depends on the script system, which is driven like an engine and continuously sends and receives data. The so-called script refers to the program of some systems in the rule reconfirmation system, and the rules are fixed. For example, in the bitcoin system, only bitcoin can be sent and received, The system allows users to edit the program rules by themselves, and then they can deploy them to the blockchain ledger. In this way, the functions of the whole blockchain system can be expanded. For example, Ethereum realizes the function of smart contract through this set of custom script system, Then specific scenario applications or real life cases, such as order logistics information and supply chain information.

7.

Blockchain technology can help us improve the security of encryption, authentication and other protection mechanisms, which is absolutely good news for the Internet of things security and DDoS Defense Community

blockchain has the potential to become an important solution for safe communities, as well as for the financial, energy and manufacturing instries. At present, verifying bitcoin transaction is one of its main uses, but this technology can also be extended to smart grid system, content delivery network and other application scenarios

how to apply blockchain to network security

whether it's protecting data integrity or using digital identification technology to prevent Internet of things devices from DDoS attacks, blockchain technology can play a key role, at least now it has shown this ability

Internet of things security and DDoS Defense Community

a blockchain startup claims that its decentralized "billing" system can help users resist DDoS attacks with traffic over 100gbps. Interestingly, the company said that this decentralized system allows users to rent their own extra bandwidth and submit their bandwidth access rights to the distributed nodes of the blockchain. When a website suffers from DDoS attacks, the website can use the leased bandwidth to mitigate DDoS attacks

improve confidentiality and data integrity

although the original design of blockchain did not consider the specific access control, now some blockchain technology implementation has solved the problems of data confidentiality and access control. In this era, any data may be tampered, which is obviously a serious problem, but the complete data encryption maliciously guarantees that the data will not be accessed or tampered by others through man in the middle attack in the transmission process

the whole IOT instry needs data integrity protection. For example, IBM's Watson IOT platform allows users to manage IOT data in a private blockchain network, which has been integrated into their big blue cloud service. In addition, Ericsson's blockchain data integrity service provides comprehensive audit, compatible and reliable data services to allow developers to use predix PAAS platform for technical implementation

one of the best applications is the transformation of our public sector and the creation of citizen centered infrastructure. This will enable the public to have their own identity and every transaction can be verified. We can use smart contracts and signed assertions to formulate elements of public services, such as benefits, etc

Internet of things & amp; Smart devices

now the attention of the whole IT community has begun to shift to the Internet of things & amp; Smart devices are on the rise, and security is absolutely one of the primary considerations. Although the Internet of things can improve our work and proction efficiency, it also means that we need to face more security risks. As a result, many companies seek to apply blockchain to protect IOT and instrial IOT (iiot) devices because blockchain technology can enhance authentication, improve data traceability and mobility, and assist record management

according to Alexey malanov, an anti-virus expert at Kaspersky laboratory, blockchain technology helps to track hacker attacks, adding:

"network intruders usually clear the permission log to hide traces of unauthorized access to devices. But if the logs are distributed in multiple devices (for example, through blockchain Technology), the risk can be reced as much as possible. "

German Klimenko, chairman of the digital economy development fund, said: "at present, the Ministry of defense is vigorously promoting it development and research, which is a good thing for the instry."

NATO and the Pentagon are also studying the "defensive" Application of blockchain. This technology is actively used to protect the system from network attacks. NATO will use blockchains to protect financial information, supply and logistics chains, while the Pentagon is developing a data transmission system to prevent hackers

in general, blockchain technology is not omnipotent, at least not yet. Whether from the perspective of technical integrity or system implementation, the current blockchain technology can not guarantee the security of the device 100%. Note: the above content comes from the Internet

8. Micro three cloud replied: blockchain developers can take some measures
one is to use professional code audit services,
the other is to understand the security coding specifications and take preventive measures
the security of cryptographic algorithm
with the development of quantum computer, it will bring great security threat to the current cryptosystem. Blockchain mainly relies on elliptic curve public key encryption algorithm to generate digital signature for secure transactions. Currently, the most commonly used ECDSA, RSA, DSA, etc. can not withstand quantum attacks in theory, and there will be greater risks. More and more researchers begin to pay attention to cryptographic algorithms that can resist quantum attacks
of course, in addition to changing the algorithm, there is another way to improve the security:
refer to bitcoin's treatment of public key address to rece the potential risk of public key disclosure. As users, especially bitcoin users, the balance after each transaction is stored in a new address to ensure that the public key of the address where bitcoin funds are stored is not leaked
security of consensus mechanism
the current consensus mechanisms include proof of work (POW), proof of stake (POS), delegated proof of stake (dpos), practical Byzantine fault tolerance (pbft), etc.

9. Blockchain technology can help us improve the security of encryption, authentication and other protection mechanisms, which is absolutely good news for the security of the Internet of things and DDoS Defense Community. Blockchain technology can also be applied to other fields. The blockchain + public service mode, which is launched by Changsha high tech Zone, is a SMIC blockchain service platform project, We are soliciting information from enterprises on the chain. In the future, relevant enterprise affairs and government affairs can cooperate on the chain. It is also one of the key blockchain projects in Hunan Province.