More advanced technology of currency blockchain
blockchain classification:
1 private chain
refers to the blockchain with certain centralized control. Only the general ledger technology of blockchain is used for bookkeeping. It can be a company or an indivial who enjoys the exclusive write permission of the blockchain. This blockchain is not very different from other distributed storage schemes. The participating nodes are only users themselves, and the access and use of data have strict authority management. Due to the existence of centralized control, alliance chain can also be considered as a private chain
features: because the user has the final say, the data inside can not be changed, and there is not much protection for the third party. Generally used for internal audit. The vice president of fire coin technology believes: there are indeed a large number of scenarios in the private chain that can meet the needs of the real world. Limited decentralization makes it easier to reach a consensus, which can make the transaction faster and more efficient, and can provide more controlled functions. Decentralization is the core value of blockchain technology. If the private chain can not make full use of the decentralized trust base constructed by the public chain in practice, its development space will be limited
2public chain
public blockchain is the earliest blockchain and the most widely used one at present. It refers to a completely decentralized blockchain like bitcoin blockchain, which is not controlled by any organization. Any indivial or group in the world can send a transaction, and the transaction can be effectively confirmed by the blockchain, and anyone can participate in the consensus process. Participants in the consensus process maintain database security through cryptography and built-in economic incentives
features: completely open, uncontrolled, rely on encryption technology to ensure security
3 alliance chain
multiple preselected nodes are designated as bookkeepers within a certain group. The generation of each block is jointly determined by all preselected nodes. Other access nodes can participate in the transaction, but not the bookkeeping process (in essence, it's still managed bookkeeping, but it's just distributed bookkeeping. How many preselected nodes are there, How to decide the bookkeeper of each block becomes the main risk point of the blockchain). Anyone else can make limited query through the open API of the blockchain
the nodes participating in the blockchain are selected in advance, and the nodes are likely to have good network connections. Other consensus algorithms without workload proof can be used on such a blockchain. For example, a blockchain has been established among 100 financial institutions, and more than 67 institutions must agree to reach a consensus
Prospect:
the development of blockchain technology has also brought changes in the operation concepts of various instries. New technologies and new concepts have promoted the new development of various instries. This driving force has a huge impact on society and the promotion of economic activities. Many new instrial phenomena will occur one after another, and the public will wait and see, It is expected that this new technology will be used by all instries and benefit all instries better
1. Blockchain links
as the name suggests, blockchain is a chain composed of blocks. Each block is divided into block head and block body (including transaction data). The block head includes the prevhash value (also known as hash value) of the previous block used to realize the block link and the random number (nonce) used to calculate the mining difficulty. The hash value of the previous block is actually the hash value of the head of the previous block, and the random number calculation rule determines which miner can obtain the right to record the block
2. Consensus mechanism
blockchain is accompanied by the birth of bitcoin, which is the basic technology architecture of bitcoin. Blockchain can be understood as an Internet-based decentralized accounting system. A decentralized digital currency system like bitcoin requires the consistency of accounting of honest nodes without a central node, which needs blockchain to complete. Therefore, the core of blockchain technology is a consensus mechanism to reach a consensus on the legitimacy of transactions between indivials without mutual trust without central control
there are four main types of consensus mechanisms in blockchain: pow, POS, dpos and distributed consistency algorithm
3. Unlocking script
script is an important technology to realize automatic verification and contract execution on blockchain. Every output of every transaction does not point to an address in the strict sense, but to a script. A script is like a set of rules that constrain how the receiver can spend the asset locked on the output
the validation of transactions also depends on scripts. At present, it depends on two kinds of scripts: Lock script and unlock script. Locking script is a condition added to the output transaction, which is realized by a script language and located in the output of the transaction. The unlocking script corresponds to the locking script. Only when the conditions required by the locking script are met can the assets corresponding to the script be spent, which is located in the input of the transaction. Many flexible conditions can be expressed by script language. Interpretation script is similar to the "virtual machine" in our programming field, which runs in every node of the blockchain network in a distributed way
4. Transaction rules
blockchain transaction is not only the basic unit of a block, but also the actual effective content recorded by the blockchain. A blockchain transaction can be a transfer, or the deployment of smart contracts and other transactions
as far as bitcoin is concerned, a transaction refers to a single payment transfer. The transaction rules are as follows:
1) the input and output of the transaction cannot be empty
2) for each input of a transaction, if its corresponding utxo output can be found in the current transaction pool, the transaction will be rejected. Because the current transaction pool is the transaction not recorded in the blockchain, and each input of the transaction should come from the confirmed utxo. If it is found in the current trading pool, it is Shuanghua trading
3) for each input in a transaction, the corresponding output must be utxo
4) each input unlocking script must verify the compliance of the transaction together with the corresponding output locking script
5. Transaction priority
the priority of blockchain transaction is determined by the blockchain protocol rules. For bitcoin, the priority of a transaction to be included in a block is determined by the time when the transaction is broadcast to the network and the amount of the transaction. With the increase of transaction broadcast time on the network and the increase of transaction chain age, the priority of transaction will be improved and eventually be included by the block. For Ethereum, the priority of the transaction is also related to the transaction fee that the publisher is willing to pay. The higher the transaction fee that the publisher is willing to pay, the higher the priority that the transaction is included in the block
6. Merkle proof
the original application of Merkle proof is bitcoin, which was described and created by Satoshi Nakamoto in 2009. Bitcoin blockchain uses Merkle proof to store transactions in each block. So that the transaction can not be tampered with, but also easy to verify whether the transaction is included in a specific block
7. RLP
RLP (recursive length prefix) is one of the main encoding methods of object serialization in Ethereum. Its purpose is to encode the sequence of arbitrary nested binary data.
first, the meaning of blockchain technology
blockchain technology is a kind of technology that uses decentralized consensus mechanism to maintain a complete, distributed and tamper proof ledger database. It can enable the participants in the blockchain to realize a unified ledger system without establishing a trust relationship. The block is a public account book, which needs multi-point maintenance; Chain is covered with timestamps, which can not be forged. Blockchain is essentially a technology that focuses on security and credibility rather than efficiency
at present, there is a database behind all systems, that is, a large account book. So it's very important who keeps this account book. Now, whose system is who will keep accounts, and the bank accounts are the records of each bank, and Alipay's account is Ali. But now in the blockchain system, everyone in the system can have the opportunity to participate in bookkeeping. If there are new transaction data changes in a certain period of time, everyone in the system can make bookkeeping. The system will judge the fastest and best bookkeeper in this period, write the recorded content into the account book, and send the content of the account book to all other people in the system for backup. In this way, everyone in the system has a complete account book
as a result, the data becomes very secure. Tamperers need to modify more than half of the system node data at the same time to truly tamper with the data. The cost of such tampering is so high that it is almost impossible. For example, bitcoin has been running for more than seven years, and countless hackers around the world have tried to attack bitcoin, but so far there have been no trading errors. It can be considered that bitcoin blockchain has been proved to be a safe and reliable system. Therefore, it can be considered that blockchain technology is a way for the whole people to participate in bookkeeping, and what it will bring is the innovation of bookkeeping.
this is the meaning of blockchain payment. Let the payment be fairer, let the payment get rid of the middleman's profit margin
there is still a serious problem in traditional payment. Many users have encountered the bad experience of being swiped and dected by the shop assistant several times because of poor signal. At this time, the shop assistant sometimes doesn't admit that he has dected too much money, and the system can't find it. Or the record is deleted by the business, and the rights and interests of users are easily trampled
and blockchain payment, every transaction, can not be tampered with. If the transaction is not successful, it will not be dected, and the business can not tamper with the transaction history. If there is more money dection, it can be seen at a glance, and anyone can view it in the blockchain browser. This is the advantage of blockchain payment.
Although bitcoin and blockchain are closely related, they cannot be equated
blockchain is the underlying technology of bitcoin
when the bitcoin system was first launched, there was no concept of blockchain, because people couldn't understand bitcoin, let alone blockchain
but in fact, up to now, we are still in a state of only knowing the concept of blockchain, and have not yet thought out the specific application landing scheme and business model. Therefore, at present, most of the blockchain applications are token, integral, pet keeping, etc. (but the application of the actual blockchain will be extremely broad), and most of the components of the actual speculation, So there is also a certain bubble, which is a bit similar to the Internet in 90s. p>