Blockchain plasma technology

1. LF CEO Ma Haobo said in the "cannon interview": the problems urgently solved by the underlying facilities of the next generation blockchain are very similar to those of Ethereum. It is an underlying decentralized computing platform. On the platform, users can easily deploy smart contracts and run them, but? LF thinks that Ethereum has three problems and hopes to solve them. The first is its overall low performance and TPS; Second, resources are not isolated. When crowdfunding for a certain contract is very popular, Ethereum network will block and other contracts cannot be executed; The third problem is reflected in the governance structure, who this blockchain belongs to, how it develops, and how to solve the problem of bifurcation.

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. Let's take bitcoin as an example:
blockchain is an important concept of bitcoin, which is essentially a decentralized database and serves as the underlying technology of bitcoin. Blockchain is a series of data blocks generated by cryptography. Each data block contains the information of a bitcoin network transaction, which is used to verify the validity of the information (anti-counterfeiting) and generate the next block
blockchain is public on the network and can be queried in every offline bitcoin wallet data. The function of bitcoin wallet depends on the confirmation with the blockchain. An effective inspection is called a confirmation. Usually, a transaction needs to obtain several confirmations. The lightweight bitcoin wallet uses online confirmation, that is, it will not download the blockchain data to the device storage
many of bitcoin's competitors also use the same design, but the workload proof and algorithm are slightly different. For example, the use of proof of interest and scrypt and so on
in addition, digital cryptocurrencies such as Laite coin, Ethereum, Weimeng coin, doggy coin and Ruitai coin also use blockchain technology.

4. The era of blockchain 1.0 is the era of digital currency, and the technical basis is:
1. Lianzhuang data block structure based on blocks
2. Network wide shared ledger
3. Asymmetric encryption
4. Source code open source
blockchain 2.0 era technical basis:
1. Smart contract; It is an application in the blockchain system. It is a business logic that can run automatically by coding. It usually has its own token and special development language
2. DAPP: it includes the user's applications, including but not limited to various cryptocurrencies, such as Ethereum wallet
3. Virtual machine: used to execute the compiled code of smart contract. Virtual machine is Turing complete
with the application and deepening of blockchain technology, the era of blockchain 3.0 has come. The mode of blockchain cooperation can be seen from behind the operation of all walks of life. Therefore, blockchain will change the way of human life widely and profoundly, so the whole life service will enter the era of blockchain. In the process of Internet development, blockchain + physical instry, blockchain e-commerce and blockchain community operation can be applied to blockchain technology
of course, 3.0 came into being with the development of modern cryptography. Today's applied cryptography is the result of cryptography 20 years ago. Therefore, in order to apply blockchain technology to more participation scenarios, especially in Internet economy and other aspects, more verification is needed to verify whether the existing encryption technology can meet the demand, and more in-depth integration of cryptographic frontier technology and continuous innovation are needed.

5. "Blockchain is a shared distributed database technology, and its advantages are mainly manifested in three aspects: distributed decentralization, no need to trust the system, tamper proof and encryption security."
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.

6. I have summarized the following two characteristics:
1. Block chain technology is a decentralized consensus mechanism to maintain a complete, distributed and tamper proof ledger database. It can enable the participants in the blockchain to achieve a unified ledger system without establishing a trust relationship. 2. Renren blockchain technology service platform does not need to develop one click to create its own blockchain system to quickly build blockchain infrastructure; One click to complete the development and deployment of blockchain applications; To provide your customers with open, transparent and credible services.

7. The blockchain of four technologies is also based on the distributed ledger technology, which can let everyone on the network settle transactions safely and safely, and the cost is very low.