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. 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
4. There must be risks, and they are high risks, because high returns are always bound with high risks. You are a little rookie who doesn't know anything. Can you make money like other people's old birds? If you are just interested in the coin circle, I suggest you don't be reluctant to spend a small amount of money to add a pay circle of the coin circle. For example, the group of Li Xiaolai, the big money in the coin circle, once cost as much as 5 million yuan. There are also some old cats and baoerye groups, but they are too far away from us ordinary people. But if you have a lot of money, it's a good deal. If it's only tens of thousands, it's suggested to add some groups with high cost performance, such as the payment group of fire chain blockchain, Zhongshen blockchain club, which are reliable, and there is a free trial period.
5. How much risk you can take and how much you will get in return. Just like in troubled times, people who rise up may fall to the ground or become the next emperor. The question is, do you dare@ Block chain God Tucao: make complaints about investment risks correctly.
6. Yes, blockchain is a high-risk project.
7. 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
