Storage is everything.

The ownership and security of a person's property fundamentally depends on the way of keeping and defining the property. In the Internet world, a large number of user data are stored on the server of the platform, so the ownership of these data is still a mystery, just as it is difficult to determine who your social ID belongs to, but the user data assets have pushed up the market value of the platform, but as a user, they have not enjoyed the market value dividend. The blockchain world has changed storage media and methods, and the ownership of assets has been delivered to individuals.

The risks faced by the blockchain system are not only attacks from external entities, but also attacks from internal participants and component failures, such as software failures. Therefore, before the implementation, it is necessary to make a risk model and recognize the special safety requirements to ensure the accurate grasp of risks and countermeasures.

1. Unique security features of blockchain technology

● (1) Security of written data

Under the action of * * * knowledge mechanism, only when most nodes (or multiple key nodes) in the whole network think that this record is correct at the same time can the authenticity of the record be recognized by the whole network and the recorded data be allowed to be written into the block.

● (2) Security of reading data

Blockchain has no inherent security restrictions on information reading, but it can control information reading to a certain extent, such as encrypting some elements on the blockchain and then giving the key to relevant participants. At the same time, the complicated knowledge agreement ensures that everyone in the system sees the same account book, which is an important means to prevent double payment.

(3) Distributed Denial of Service

The distributed architecture of the anti-attack blockchain gives it the characteristics of point-to-point and multi-redundancy, and there is no single point of failure, so its response to denial of service attacks is much more flexible than that of centralized systems. Even if one node fails, other nodes will not be affected, and users connected to the failed node cannot connect to the system unless there is a mechanism to support them to connect to other nodes.

2. The security challenges and countermeasures of blockchain technology.

● (1) The network is open and undefended.

For the public chain network, all data are transmitted on the public network, and all nodes joining the network can connect and accept connections from other nodes without obstacles, and there is no protection such as authentication at the network layer. The coping strategy for this kind of risk is to require higher privacy and carefully control the network connection. For industries with high security, such as the financial industry, it is recommended to use a dedicated line to access the blockchain network, authenticate the connected connections, exclude unauthorized nodes from accessing, avoid data leakage, and prevent network attacks through firewall security protection at the protocol stack level.

● (2) Privacy

The transaction data on the public chain can be seen all over the network, and the public can track these transactions. Anyone can draw a conclusion about something by observing the blockchain, which is not conducive to the legitimate privacy protection of individuals or institutions. The coping strategies for this risk are:

First of all, the certification authority conducts transactions on behalf of users of the blockchain, and user data and personal behavior will not enter the blockchain.

Second, the whole network broadcast mode is not used, and the transmission of transaction data is limited to the nodes that are conducting related transactions.

Third, access to user data is controlled by permissions, so that visitors with keys can decrypt and access the data.

Fourth, adopt privacy protection algorithms such as "zero knowledge proof" to avoid privacy exposure.

(3) Computational force

Blockchain solutions using workload proof are all facing the problem of 5 1% computing power attack. With the gradual concentration of computing power, there are objectively organizations with more than 50% computing power. Without improvement, it is not excluded that they will gradually evolve into the jungle law of the jungle. The coping strategy for this kind of risk is to combine the algorithm with realistic constraints, such as joint control through asset mortgage, law and supervision.