区块链至少需要几个节点组成,区块链至少需要几个节点

近年来，随着区块链技术的发展，人们对区块链的关注度也越来越高。区块链是一种分布式账本技术，它可以实现分布式数据存储、共识机制、加密算法等。那么，区块链至少需要几个节点组成呢？

要想让区块链系统正常运行，至少需要三个节点。这三个节点是挖矿节点、全节点和矿池节点。挖矿节点是参与挖矿的节点，它们可以挖掘新的区块，并将它们添加到区块链中。全节点是完整的区块链节点，它们可以跟踪区块链上的所有交易，并将它们存储在本地节点上。矿池节点是一种特殊的节点，它们可以与其他节点一起参与挖矿，以获得更多的收益。

此外，为了让区块链系统能够正常工作，需要一定数量的节点，这个数量取决于区块链的类型。例如，比特币和以太坊等主流区块链系统需要至少10个节点才能正常运行，而更小的系统可能只需要3个节点。

另外，为了确保区块链的安全性，不同的节点需要在不同的地方运行，以防止单点故障。因此，节点的数量和分布也非常重要。

总之，区块链至少需要三个节点来组成，这三个节点分别是挖矿节点、全节点和矿池节点。为了确保区块链系统的安全性，节点的数量和分布也非常重要。

Ⅰ Does the Bitcoin blockchain have a blockchain for every Bitcoin? Does each node have complete blockchain data?

Bitcoin block Is there a blockchain for every Bitcoin? No, blocks store transactions. In the early stage, if you successfully create a block, you will get a coin. In the later stage, you can only get the fees paid by the transaction. A currency is a string of digital signatures sent by the previous owner to the recipient. Everyone can see who owns the currency from the transaction.
Does each node have complete blockchain data? The node you are talking about refers to a user node? A user node needs to retain a copy of the block header of the longest proof-of-work chain, so if it knows the data of all block headers, it can move forward to know the data on all blockchains, but not all of them are saved. A block header is very small, only 80 bytes, and can be saved because the generation of nodes is very slow. Even if it changes over time, the volume is not too large now.

Ⅱ I just learned about it. Can anyone tell me what blockchain is and how to explain blockchain technology in a simple way?

The way in which everyone keeps accounts together is also called "distributed ” or “decentralized” because everyone keeps accounts and the accuracy of the accounts is determined by program algorithms rather than an authoritative organization.

This is the blockchain. The core is finished. The blockchain is as simple as a common ledger

The six core algorithms of blockchain technology:

Blockchain Core Algorithm 1: Byzantine Agreement

The story of Byzantium goes like this: The Byzantine Empire has huge wealth, and its 10 neighboring countries have been around for a long time, but Byzantium’s high walls stand tall. It was so impregnable that no single neighbor could successfully invade. Any invasion by a single neighbor will fail, and it is also possible that it will be invaded by 9 other neighbors. The Byzantine Empire's defensive capabilities were so strong that at least half of its ten neighbors had to attack at the same time to be able to break through. However, if one or several of the neighbors agree to attack together, but betrayal occurs during the actual process, then the invaders may all be annihilated. So each party acted cautiously and did not dare to trust its neighbors easily. This is the Byzantine Generals Problem.

Blockchain Core Algorithm 2: Asymmetric Encryption Technology

In the above-mentioned Byzantine Agreement, if several of the 10 generals initiate messages at the same time, it will inevitably cause chaos in the system. As a result, each has its own attack time plan, making it difficult to coordinate actions. Anyone can launch an offensive message, but who will send it? In fact, this only requires adding a cost, that is: only one node can spread information within a period of time. When a node sends a unified attack message, each node must sign and stamp the message from the initiator to confirm their identity.

Blockchain Core Algorithm Three: Fault Tolerance Issues

We assume that in this network, messages may be lost, damaged, delayed, and sent repeatedly, and they must be accepted smoothly.The order is inconsistent with the order sent. In addition, the behavior of nodes can be arbitrary: they can join and exit the network at any time, they can discard messages, forge messages, stop working, etc. Various human or non-human failures may also occur. Our algorithm provides excellent fault tolerance for a consensus system composed of consensus nodes. This fault tolerance includes both security and availability, and is applicable to any network environment.

Blockchain Core Algorithm Four: Paxos Algorithm (Consistency Algorithm)

The problem solved by the Paxos algorithm is how a distributed system can reach agreement on a certain value (resolution). A typical scenario is that in a distributed database system, if the initial state of each node is consistent and each node performs the same sequence of operations, then they can finally obtain a consistent state. In order to ensure that each node executes the same command sequence, a "consistency algorithm" needs to be executed on each instruction to ensure that the instructions seen by each node are consistent. A general consensus algorithm can be applied in many scenarios and is an important issue in distributed computing. There are two models for node communication: shared memory and message passing. The Paxos algorithm is a consensus algorithm based on the message passing model.

Blockchain Core Algorithm Five: Consensus Mechanism

The blockchain consensus algorithm is mainly proof of work and proof of equity. Taking Bitcoin as an example, in fact, from a technical point of view, PoW can be regarded as reused Hashcash. Generating proof of work is a random process in terms of probability. To mine a new confidential currency, when generating a block, all participants must agree, and the miner must obtain PoW proof of work for all data in the block. At the same time, miners must constantly observe and adjust the difficulty of this work, because the network requirement is to generate a block every 10 minutes on average.

Blockchain Core Algorithm 6: Distributed storage is a data storage technology that uses the disk space on each machine through the network and combines these dispersed storage resources into a virtual storage device. Decentralized storage in every corner of the network. Therefore, distributed storage technology does not store complete data on each computer, but splits the data and stores it in different computers. It's like storing 100 eggs, not in the same basket, but in different places. The total sum is 100. If you want to know more, you can use the Internet to search. Internet search results - little knowledge

Ⅲ Why does a transaction in the blockchain require 6 blocks of confirmation? Is it a hard rule?

This is not a hard and fast rule and has nothing to do with the blockchain. There is a relationship between the algorithm of this coin and the confirmation method of each coin is different, so this is not a hard and fast rule.
The number of confirmations for Bitcoin, Ritecoin, Litecoin, and Dogecoin are all different.

IV Introduction to Blockchain

Wikipedia describes the blockchain as follows:

 A blockchain, originally block chain, is a continuously growing list of records, called blocks, which are linked and secured using cryptography. Each block typically contains a cryptographic hash of the previous block, a timestamp and transaction data. By design, a blockchain is inherently resistant to modification of the data. It is "an open, distributed ledger that can record transactions efficiently and in a verifiable and permanent way". For use as a distributed ledger, a blockchain is typically managed by a peer-to-peer network collectively adhering to a protocol for validating new blocks. Once recorded, the data in any given block cannot be altered retroactively without the alteration of all subsequent blocks, which requires collusion of the network majority.
< br /> Simply put, the blockchain system includes the following elements:

Data: The data stored in the blockchain can be transaction records or smart contracts and other information;
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Block: used to save data; a block has a block header, which contains the hash value of this block, the hash value and timestamp of the previous block header, block ID and other information;

Chain: Blocks form a linked list. The first block is called the founding block, and subsequentBlocks are added to the chain as mentioned above, and can only be added but not deleted or modified;

Distributed: It is a distributed system. Different from other distributed systems, the system Each node will save complete data (some practices may be different, but at least a majority of nodes)

Safe: the data will not be tampered with, each block records its previous area The hash value of the block will change if the content of the block is changed, which means that all blocks after the block must be modified; furthermore, all nodes store complete linked lists, and it is possible to change a single node. If so, then it is basically difficult to change all (most) nodes. It is said that it is easy to break one chopstick, but it is difficult to break a hundred chopsticks.

Transparent: Other nodes will perceive the operation of any node, and the data stored on the chain will be verified, which further provides security and mutual trust.

Decentralization: There are no central nodes or key nodes, thus providing high reliability, but there are also distributed system consistency issues. Now different products use different consistency algorithms, such as Bit POW in the currency, Ethereum POW+POS, etc.

From the technical characteristics of the blockchain, we can see that it is suitable for some scenarios that require cross-organizations/individuals.

WIP

IV 2018-09-05Xiaobai learns blockchain-21 super nodes

1. What is a super node

The so-called super nodes refer to those nodes in the EOS network that collect transaction information and package it into blocks. They can also be simply understood as the "miners" who package blocks.

2. Why are there 21 super nodes

We know that centralization has high efficiency but low security; decentralization has high security but low efficiency. . Therefore, the blockchain world has always wanted to find a balance between centralization and decentralization to take into account security and efficiency. EOS is based on this. In order to improve the efficiency of network operation, it responds by reducing nodes and uses voting to determine 21 nodes. In addition, there are 100 alternative node witnesses. These nodes may be the right ones in BM’s view. A good balance of efficiency and security.

3. Benefits of becoming a super node

It is mentioned in the paper that EOS will issue an additional 5% of tokens to those who maintain nodes every year. What is the concept of this money? The total amount of EOS is one billion, 5% is 50 million; the current price of EOS is calculated at 40 RMB, and it is divided among 21 nodes. Each node still earns close to 100 million in annual income. Once the price of EOS soars, the future benefits of these super nodes will be immeasurable. Faced with such huge benefits, big guys from all over the world will come to run for nodes.Get a piece of the pie.

4. The significance of super nodes to currency holders

In order to obtain votes, teams competing for super nodes either buy a large amount of EOS or offer more attractive rewards. When canvassing votes, some teams will use the proceeds to distribute dividends to everyone (BM does not support such vote buying), and some will provide other benefits. Secondly, voting must use EOS, which injects value relative to the EOS currency, making it a more valuable currency.

VI The three key points in blockchain technology are:

The consensus algorithm, the use of asymmetric encryption for data signature, and the storage of chain blocks. Blockchain is a chain composed of blocks one after another. Each block stores a certain amount of information, and they are connected into a chain in the order in which they were generated. This chain is saved in all servers. As long as one server in the entire system can work, the entire blockchain is safe. These servers are called nodes in the blockchain system, and they provide storage space and computing power support for the entire blockchain system. If you want to modify the information in the blockchain, you must obtain the consent of more than half of the nodes and modify the information in all nodes. These nodes are usually in the hands of different subjects, so tampering with the information in the blockchain is a serious problem. An extremely difficult thing. Compared with traditional networks, blockchain has two core characteristics: first, data is difficult to tamper with, and second, it is decentralized. Based on these two characteristics, the information recorded in the blockchain is more authentic and reliable, and can help solve the problem of people's mutual distrust. Blockchain originated from Bitcoin. On November 1, 2008, a person claiming to be Satoshi Nakamoto published the article "Bitcoin: A Peer-to-Peer Electronic Cash System", which elaborated on P2P network technology and encryption technology. , timestamp technology, blockchain technology and other electronic cash system architectural concepts, which marks the birth of Bitcoin. Two months later, the theory came into practice, and on January 3, 2009, the first genesis block with serial number 0 was born. A few days later, block number 1 appeared on January 9, 2009, and was connected to the genesis block number 0 to form a chain, marking the birth of the blockchain. Blockchain in the narrow sense is a chained data structure that combines data blocks in a sequential manner in chronological order, and is a cryptographically guaranteed distributed ledger that cannot be tampered with or forged. Generalized blockchain technology uses block chain data structures to verify and store data, uses distributed node consensus algorithms to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses smart contracts composed of automated script codes. , a new distributed infrastructure and computing paradigm for programming and manipulating data.

VII Nodes in the blockchain network include

Nodes in the blockchain network include mobile phones, mining machines, servers, etc.
Nodes refer to computers in the blockchain network. Blockchains are participated by a large number of individuals or family users. Each individual or family is a node of the blockchain.
BlockThe chain is composed of small blocks. Everyone who forms a block node does not know each other, but they trust each other because they also have a common purpose, which is to obtain the rewards of the mechanism.

VIII Components of Blockchain

The components of Blockchain are as follows:

Openness: Blockchain The system data is open and transparent, and everyone can participate. For example, when renting a house, you can know the previous rental information of the house and whether there have been any problems. Of course, some personal private information is encrypted.

Autonomy: The blockchain adopts consensus-based specifications and protocols (such as a set of open and transparent algorithms), and then each node operates according to this specification, so that everything is completed by machines , there is no human element. This changes trust in people to trust in machines, and any human intervention has no effect.

The information cannot be tampered with: If the information is stored in the blockchain, it will be saved permanently and there is no way to change it. As for the 51% attack, it is basically impossible to achieve.

Anonymity: There is no personal information on the blockchain, because it is all encrypted and is a string of letters and numbers, so your various ID card information and phone number will not appear. Numbers are being resold.

Ⅸ Are different nodes in the blockchain not equal?

Yes, different nodes in the blockchain are not equal.
Reason:
1. Different node types: In a blockchain, different types of nodes can exist in rentable space, such as full nodes, light nodes, miner nodes, etc. Different types of nodes have different functions and roles, and therefore are not equivalent.
2. Different storage capacities: Some nodes may have larger storage capacity to store more transaction data and block data, while some nodes may only have smaller storage capacity and may only retain the most recent areas. block of data.
3. Different processing capabilities: Since different nodes have different hardware and network speeds, the nodes have different capabilities in processing transactions and verifying blocks.
4. Different degrees of participation: In a blockchain, some high-level friend nodes may have a higher degree of participation, that is, they verify transactions and blocks by participating in the process of the consensus algorithm, thereby having a higher degree of participation. more rights to participate in decision-making.
Therefore, although nodes all play an important role in the network, different nodes have different roles, functions, processing capabilities, and participation, so they are not completely equivalent.