Blockchain true random number

1. blockchain technology uses mathematical methods to achieve distributed accounting and solve the trust problem, so as to complete the decentralization, which will bring far-reaching influence in many fields such as communication, finance, Internet of things, government management and so on
blockchain refers to the technical solution of collective maintenance of a reliable database through centralization and distrust in the past, and it is a technical way for the whole people to participate in bookkeeping. Previous bookkeeping methods were all centralized and needed centralized intermediary, whether it was traditional government, financial institutions, notarization institutions or emerging e-commerce platform and online payment platform
in economic hypothesis, information is sufficient. In fact, it is precisely because of insufficient information that there are very large intermediaries. The existence of intermediaries increases the transaction cost and raises the transaction threshold. In essence, blockchain technology is a large-scale collaboration tool. It makes direct value transfer possible by using pure technology for the first time, and continues the trend of Internet decentralization and disintermediation. Disintermediated blockchain technology will greatly subvert the information intermediary instry
blockchain technology is the basic technology for building bitcoin data structure and encrypted transmission of transaction information, which realizes the issue and transaction of bitcoin. The core of blockchain technology is that all the current participating nodes jointly maintain the transaction and database, so that the transaction is based on the principle of cryptography rather than trust, so that any agreed parties can directly carry out payment transactions without the participation of a third party
technically, a block is a data structure for recording transactions, reflecting the capital flow of a transaction. In the system, the transaction blocks are connected to form a main chain, and all the nodes participating in the calculation record the main chain or part of the main chain
a block contains the following three parts: transaction information, hash formed by the previous block and random number. Transaction information is the task data carried by the block, including the private keys of both parties, the number of transactions, the digital signature of electronic currency, etc; The hash hash formed by the previous block is used to connect the blocks and realize the sequence of past transactions; Random number is the core of the transaction. All nodes compete to calculate the answer of the random number. The node that gets the answer the fastest generates a new block and broadcasts it to all nodes for updating, so as to complete a transaction.

2. Introction to seven core technologies of blockchain operation on January 15, 2018
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.

3. How can blockchain be connected in sequence
blockchain is composed of a series of blocks generated by cryptographic algorithm. Each block is filled with transaction records, and the blocks are connected in sequence to form a chain structure, which is the blockchain ledger
taking bitcoin as an example, when miners generate new blocks, they need to calculate the new hash value and random number according to the hash value of the previous block, the new transaction block and the random number. In other words, each block is generated on the basis of the previous block data, which ensures the uniqueness of the blockchain data
because subtle changes in transaction records will completely change the result of hash value, miners can't cheat when competing for computing power. Each miner must wait until the previous block is generated before starting to calculate the qualified random number according to the data of the previous block, which ensures the fairness of mining.

4. It's a public list of all the transactions that have been sent. It ensures that everyone knows the real owner (address) of each bitcoin. All full function nodes on the network will keep a of the blockchain< Br > block is an independent unit in the blockchain. Each block contains the hash value of the previous block (so it is impossible for someone to delete or modify any block on the blockchain without making some hash values on the blockchain mismatched), as well as as as many unconfirmed transactions that can be found on the network, and a number called nonce random number. Someone who is creating a block must find a suitable nonce random number so that the hash value of the block is lower than a certain threshold (the target value). This can only be done by trying all the random numbers one after another until a random number with the desired hash value is found. The lower the target value is, the more difficult it is to find a suitable random number. Deliberately making block creation so difficult is to prevent someone from spending bitcoin, and then create and promote his own blockchain that does not include the transaction that shows that bitcoin has been spent just now, erase the transaction record once and allow him to spend bitcoin twice. When a valid block is created, it will be distributed to the whole network, and then search for the next block based on this block.

5. With the combination of 5g and robot technology, new consumer electronics procts are emerging. AI solves the problem of machine understanding the world and human-computer interaction. 5g expands the mobile boundary of the robot, and provides more computing power and storage space for the robot (cloud cooperative robot)< According to the IFR classification method, robots can be roughly divided into instrial robots and service robots. Traditional instrial robots are mainly used in automobile and parts, electronic manufacturing, metal and machinery, food processing and so on. Its main feature is to complete the specified action along the specified path according to the predetermined procere. How can AI / 5G enable robots

the application of AI Artificial Intelligence has given birth to service robots. Service robot covers a wide range, including medical, logistics, agriculture, commerce, civil and other aspects. Through the use of AI technology, through data collection, analysis and calculation, service robot can learn human behavior, understand human intention and cooperate with human< According to IFR calculation, the global robot market in 2017 reached US $23.2 billion, of which the instrial robot market reached US $14.7 billion, with 85 robots per 10000 people. The rest is the service robot market, with a market size of US $8.5 billion

by 2030, the robot market is expected to reach 102.8 billion US dollars, about 20% of the smartphone market. Service robots will reach US $56.1 billion, maintaining a compound annual growth rate of 16%, which is faster than that of instrial robots. After two years of rapid development in 2017 and 2018, the number and amount of financing in the artificial intelligence instry in 2019 showed a precipice like decline, capital concentrated in the head enterprises one after another, and the survival of small companies was difficult. Even the head companies have encountered obstacles on the way to listing, and the news of layoffs is constantly shrinking. From the external environment, everyone's life is not easy

cheetah global think tank believes that the future of artificial intelligence is not always full of flowers and applause. If artificial intelligence really wants to lead the next decade, it must be that practitioners abandon the flashy valuation, focus on procts, take root in technology, and strive for the realization of the scene overnight

pencil recommendation:

after two years of rapid development in 2017 and 2018, the number and amount of financing in the artificial intelligence instry will show a precipice like decline in 2019, capital will be concentrated in the head enterprises one after another, and small companies will have a hard time surviving. Even the head companies have encountered obstacles on the way to listing, and the news of layoffs is constantly shrinking. From the external environment, everyone's life is not easy

cheetah global think tank believes that the future of artificial intelligence is not always full of flowers and applause. If artificial intelligence really wants to lead the next decade, it must be that practitioners abandon the flashy valuation, focus on procts, take root in technology, and strive for the realization of the scene overnight<

source | cheetah global think tank

authors | Zhou Ting, pan Xinghan, Li Xin, Xiao Haiyan

report guidance | Han Jianqi, Zhou Ting

I. foreword

I. foreword

if you want to establish a biography for artificial intelligence, 2019 is destined to be a different year of seeking normality. Difficult and awkward, rooted and stick to, multiple complex emotions interweave in this year

difficult! After two years of rapid development in 2017 and 2018, the number and amount of financing in the artificial intelligence instry in 2019 showed a precipice like decline, capital concentrated in the head enterprises one after another, and the survival of small companies was difficult. Even the head companies have encountered obstacles on the way to listing, and the news of layoffs is constantly shrinking. From the external environment, everyone's life is not easy

awkward! 2019 is also a year of disillusionment. Artificial intelligence was once seen as the next opportunity to create a 10 billion dollar giant after the mobile Internet. But in 2019, before the arrival of general artificial intelligence, it is not as versatile as people think. The public's enthusiasm for artificial intelligence has also decreased a lot. How many people are still concerned about the man-machine battle between Li Shishi and Korean go AI "Han Dou" in December this year<

we should cultivate grain, build high walls and become king slowly. Cheetah global think tank believes that the future of artificial intelligence is not always full of flowers and applause. If artificial intelligence really wants to lead the next decade, practitioners must abandon the flashy valuation, focus on procts, take root in technology and seize the day in the scene

next, cheetah global think tank will comprehensively scan the development of artificial intelligence in 2019 from the aspects of policy, capital, technology, intelligent service robots, AI application scenarios, etc., trying to show you a more comprehensive commercialization of artificial intelligence in 2019.

6. 1. Front block hash value. It is used for pre index block
2, mining difficulty, random value (used for workload proof calculation), time stamp
3 and Merkel tree, which can summarize and quickly summarize the root data of all transaction data in the verification block.