Blockchain technology is a distributed database that maintains a growing set of data records, which are associated with all previously written data through cryptography. , making it difficult for third parties or even the owner of the node to tamper with it. Blocks contain the data that actually needs to be saved in the database. These data are organized into blocks and written to the database. Chain usually refers to the use of Merkle tree and other methods to verify whether all current blocks have been modified. Coders who have used Git have long been familiar with this. Think back to how to modify the history of Git.
Some currently known blockchain technology applications generally fall into these three categories:
Public blockchain Examples: Bitcoin, Ethereum Frontier. The data on the public blockchain is accessible to everyone, and everyone can issue transactions waiting to be written to the blockchain. Participants in the identification process (corresponding to miners in Bitcoin) maintain the security of the database through cryptography and built-in economic incentives. Public blockchains are completely distributed.
Collaborative blockchain (federated blockchain) Example: Hyperledger and the auditing system attempted by accountants such as Deloitte. The nodes participating in the blockchain are selected in advance, and there are likely to be good network connections between the nodes. Other consensus algorithms other than proof of work can be used on such a blockchain. For example, if a certain blockchain is established among 100 financial institutions, it is stipulated that more than 67 institutions must agree to achieve a consensus. knowledge. The data on such a blockchain can be public or internal to these node participants. Distributed in a partial sense.
Private blockchain Example: Eris Industries. The only participating nodes are the users themselves, and data access and use are subject to strict permission management. Most of the internally used blockchain technologies announced by some financial institutions recently are vague, but they are likely to be within this range.