Blockchain contract log
Seeing some answers to the debate on the definition of blockchain, I suddenly realize that my answer to this explanation principle has always been directed at bitcoin. There is no specific and unique answer in the instry between the definition of blockchain. Here I first summarize the characteristics of "blockchain" according to the papers I read:
1; Hash chain & quot There are several nodes participating in the system operation (distributed)
3. Reach a consensus on the consistency of basic data (consensus agreement / algorithm) through a certain protocol or algorithm
since bitcoin is currently one of the most typical and influential applications of blockchain, it will be much easier to understand how bitcoin uses blockchain before understanding other forms of blockchain applications
smart contract is a contract that uses computer language instead of legal language to record terms. Once it is written, it can be trusted by users. The terms of the contract cannot be changed, so the contract cannot be changed. If the procere meets the conditions, it will be carried out, and there is no human interference to ensure absolute fairness
three technical features of smart contract
● data transparency
all data on the blockchain are open and transparent, so the data processing of smart contract is also open and transparent, and any party can view its code and data at runtime
● can't tamper
all data of the blockchain itself can't be tampered, so the code of the smart contract deployed on the blockchain and the data generated by the operation can't be tampered, and the node running the smart contract doesn't have to worry about malicious modification of the code and data by other nodes
● permanent operation
the number of nodes supporting the blockchain network often reaches hundreds or even thousands. The failure of some nodes will not lead to the stop of the smart contract, and its reliability is close to permanent operation in theory, which ensures that the smart contract can be as effective as the paper contract at all times.
three characteristics of smart contract in blockchain can be summed up:
1) decentralization. It doesn't rely on the centralized server and runs automatically through the network nodes
2) good trust mechanism. The crisis of trust is greatly reced, and it is not necessary to consider whether the participation is trustworthy
3) high degree of autonomy. Once the condition is triggered, the contract will be executed automatically without interference
to put it simply, we should make an appointment to trade a certain amount of certain goods at a certain time and place in the future.
in a narrow sense, blockchain is a kind of chained data structure, which is composed of data blocks connected in sequence according to the time sequence, and is a distributed account book that can not be tampered with and forged by cryptography. In a broad sense, blockchain technology is a new distributed infrastructure and computing paradigm, which uses blockchain data structure to verify and store data, uses distributed node consensus algorithm to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses intelligent contract composed of automated script code to program and operate data.
1-security problem: one of the key problems is security and trust. The smart contract system is designed to be an environment without trust, which means that the mistakes can not be corrected
2 - Privacy: one of the challenges of effective use of blockchain is to provide thorough transparency
3 - unexpected scenario problem: smart contract sounds very good, but how to correctly and appropriately handle the contract execution in unexpected scenarios is a problem.