Snapshot blockchain

2. Nodes are the places where the blocks are connected, and the blocks need to be chained to be useful
core analysis:
1. Transparency, 2. Openness, 3. Information can not be tampered with, 4. Decentralization,
5. Detailed analysis
blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies. The so-called consensus mechanism is a mathematical algorithm to establish trust and obtain interests between different nodes in the blockchain system
1. In a narrow sense, blockchain is a kind of chained data structure composed of data blocks connected in sequence according to the time sequence, and it can not be tampered with and forged by cryptography
2. Broadly speaking, blockchain technology uses blockchain data structure to verify and store data, uses distributed node consensus algorithm to generate and update data, and uses cryptography to ensure the security of data transmission and access It is a new distributed infrastructure and computing method to program and operate data by using intelligent contract composed of automated script code.

3.

It's said that the currency circle has been going on for one day and the stock market has been going on for one year. Although it's a bit exaggerated, it's not unreasonable. In recent days, bitcoin has gone up sharply, but it has come down slightly today. It's estimated that no one can match the speed of the bull bear conversion in the currency circle. However, among many virtual currencies, how can we find high-quality projects? Xiaobian thinks that the bull market is not surprising. The key point is that the bear market still insists on giving weekly reports, at least for the projects with reliable teams. Today Xiaobian still brings you weekly reports of some high-quality projects. The following is the latest weekly project progress report (April 9-April 15, 2018) released by ubtc team. The specific information is as follows:

pre upgrade of Ub smart contract:

smart contract is one of the major milestones of the technology roadmap of bit fed project. In order to prepare for the implementation of smart contract on UB, the UB team made some adjustments on April 10, 2018, as follows:

1. The block speed was adjusted from 10 minutes to 1 minute

2. The difficulty adjustment cycle was once for 10 blocks

3. Block reward was adjusted to 1 ubtc

The total amount of ubtc was adjusted from 21 million to 20 million

The mature period of reward was 7200 blocks

this adjustment requires users to download the latest version of the wallet to ensure that subsequent use will not be affected

wallet download link: https://www.ub.com/project/wallet

R & D:

1

2. Ubtc contract function continued internal test and bug repair

3. Ubtc contract function test documents continue to improve

4. Gjavac, gsharpc, uvmassassembler, uvmpackagegpc organize the code and open source on GitHub

5

Market:

1. Anybit mobile wallet charging UB award UB activity starts at 8:00 p.m. Beijing time on April 4, 2018, and ends at 8:00 p.m. Beijing time on April 15, 2018. During the activity, users who download anybit and recharge ubtc will get 1% reward, up to 1 ubtc. The event is limited to the top 1000

the reward is calculated based on the balance of ubtc at 8:00 p.m. Beijing time on April 15, 2018. The reward ubtc will be uniformly distributed to the corresponding ubtc address on April 16

2. The UB team held a fan meeting in Genesis block, Wanchai, Hong Kong from 7:00 to 9:00 p.m. on April 9. Mr. Wouter van der schagt, director and project CEO of Ub foundation, introced the project progress and planning to the fans. UB's major fan communities (wechat group, telegraph group, QQ group, beechat group, microblog, twitter, etc.) carried out real-time live picture push

3. On April 9, the microblog of "UB global support association" held a comment lottery to send UB customized hat and coat. Under the supervision and notarization of Weibo official lottery tool @ Weibo lottery platform, an enthusiastic fan in Ningbo was lucky to win. The fan has already received the prize, and in the microblog @ quiet style quiet style sun out the picture

4. On the 14th, UB team sent representatives to participate in the [chaine] blockchain Technology Salon Hosted by Babbitt and had interactive exchanges with the guests present. The salon was held in Yulong international building, Huli District, Xiamen city

5. Enthusiastic fans made the relevant expression pack (animation) for UB's upgrade and adjustment on the 10th, and spread it on wechat group

6, UB subscription number WeChat official account will be on the way to sign the lottery every day. Please look forward to it! p>

community release:

1. The last snapshot of issuing ubtc to Eth and LTC communities was completed on April 11, and the qualified addresses were released on May 2. Please refer to UB website for details www.ub.com The announcement in the news section on March 18

about ubtc:

unitedbitcoin, referred to as UB, code ubtc. UB is not only an upgraded version of bitcoin, but also a leading global blockchain ecosystem. UB is headed by Jeff garzik, a veteran of bitcoin, a core developer of bitcoin and a leader in the blockchain field

UB 100% inherits bitcoin's blockchain and upgrades and optimizes it. The upgrade and optimization of Ub include expanding the block size to 8MB, supporting segwit isolation witness, adding smart contract and lightning network, etc

UB is committed to bringing the inactive bitcoin credit into full play. Finally, based on these credits, we can issue stable currency anchored by legal currency, which can be used in a wide, fast, efficient and intelligent business society

at present, UB team has developed anybit mobile wallet app (anybit is a decentralized multi currency wallet APP), core, core QT and electrum wallet (electrum is a lightweight wallet supporting multi signature), and released a complete blockchain browser

more than 18 trading platforms around the world support ubtc trading

4.

In fact, airdrop candy is a stage when many new projects get token chips at almost zero cost. It is given away as a gift. However, e to its excellent publicity effect, diffusion ability and the myth of many times making no profit at all, the concept of airdrop has been put on the altar

it is generally called airdrop, candy airdrop, virtual currency airdrop, digital currency airdrop, token airdrop, free mining and coin circle airdrop. In some English regions, it is also classified as freetoken, freemoney and candy

in particular, airdrop not only fills the income of many marketing staff, but also creates a wave of myth of sudden wealth

Airdropalert:

airdropalert http://AirdropAlert.Com It is the world's first airdrop website, officially operating in August 2017. It is a well-known English airdrop website, with the largest search volume of airdrop keywords related to Google blockchain

website:[ http://AirdropAlert.Com ]

domain name features: English grammar style, common double spelling composition, airdrop affinity. The suffix adopts. Com (the most popular and oldest in the world), which is a typical portal operation mode

AirdropAlert.com - Never miss a Free Crypto Airdrop again! Airdropalert. Com

2. (Chinese / English) currency airdrop tokenairdrop

currency airdrop http://Tokenairdrop.org It is the second airdrop website in the world, officially operating in September 2017, and providing Chinese and English services at the same time, mainly in Chinese. It officially operated in September 2017 and appeared at the same time as airdrop alert. Website style is relatively simple, without too much information, stable style, always give people a sense of home. The second largest airdrop website in the world, with the largest number of search results of Internet, Google and 360

website:[ http://TokenAirdrop.Org ][ http://TokenAirdrop.Com ][ http://CoinAirdrop.Org ]

domain name features: token / coin + airdrop double spelling literal translation domain name, Chinese and English airdrop affinity. The suffix uses. Org (the strongest search engine trust level) and. Com (the most popular and oldest domain name), which shows that the operator is very forward-looking and operates in a novelty hunting mode

coin airdrop - high quality candy airdrop & amp; Virtual currency airdrop & amp; Digital currency airdrop & amp; Token airdrop & amp; Empty Coin & amp; All the free money! The most professional candy airdrop Network - blockchain airdrop Chinese flagship- TokenAirdrop_ Orgtokenairdrop.org

3. (English) airdropking

airdropking http://AirdropKing.IO It appeared later, but it rose abruptly in the field of telegram, and became the third largest airdrop website in the world

website:[ http://AirdropKing.IO ]

domain name style airdropking is an aggressive combination of domain names. IO suffix tells visitors that it is a blockchain technology theme website

Candyairdrop.com uses the. COM domain name, which is regular and mainly updates the Chinese airdrop information

website: http://CandyAirdrop.Com

these four stations all support HTTP and HTTPS, which is updated timely

5.

blockchain (English: blockchain or block chain) is a kind of distributed database . You may have heard about bitcoin, which is the core technology. Blockchain is a series of data blocks generated by cryptography. Each data block contains the information of a network transaction, which is used to verify the validity of the information and generate the next block. In a popular concept, blockchain is an account that everyone can keep. In a company or organization, most people only have the right to keep accounts, while only a few people with professional training have the right to keep accounts. Of course, blockchain is not an account book in the traditional sense. It has the following three key points in technical principle: first, decentralization. In a network practicing blockchain technology, each computer covered by it can read and add records. From the perspective of account book, they are the people who keep accounts together, and there is no authoritative person to guide and correct them. Second, asymmetric encryption. Although everyone can remember this account, they will not be able to read it unless they are in the Bureau. Because, in the accounting process, everyone follows the unified encryption rules, but when reading, they must use their own unique decryption method. Therefore, although everyone keeps this constantly updated account, the part they can read is only the one they can decrypt, that is, the part related to themselves. Third, time stamp. That is, time stamp (English: timestamp), refers to the string or coded information used to identify the recorded time and date. Each block on the blockchain is arranged in sequence according to the time it is generated, and is confirmed by collective authentication. Moreover, previous records cannot be modified. Just like in an account, we can index and verify the previous content through the records after a point in time. Once these contents are confirmed, it will be more difficult to tamper with them

blockchain technology is to maintain a growing distributed database of data records. These data are associated with all the data written before through cryptography technology, which makes it difficult for the third party or even the owner of the node to tamper with. Block contains the data that need to be saved in the database, and these data are written into the database through block organization. Chain usually refers to the use of Merkle tree and other methods to check whether all the current blocks have been modified. This is familiar to code farmers who have used git for a long time. Recall how to modify git's history

blockchain technology is mainly divided into three categories, which are open, collaborative and private

public blockchain

example: bitcoin, Ethereum frontier. The data on the public blockchain can be accessed by all people, and all people can issue transactions waiting to be written into the blockchain. Participants in the consensus process (corresponding to the miners in bitcoin) maintain the security of the database through cryptography technology and built-in economic incentives. Open blockchain is completely distributed

highlights and pain points: the open blockchain is completely distributed and has all the characteristics of bitcoin. However, it needs sufficient cost to maintain the system operation and relies on built-in incentives. At present, only bitcoin in the public blockchain is safe enough. If the algorithm is the same as bitcoin, it will be safe; There are no built-in rewards, but they are not; It's easy to concentrate on the attack of computing power (for example, as long as the raid sweeps goods and a large number of graphics cards), and take jujube pills. The more valuable the data on the open blockchain is, the more important it is to examine its security, transaction cost and system scalability

federated blockchain

example: audit system tried by hyperledger and Deloitte. The nodes participating in the blockchain are selected in advance, and there is likely to be a good network connection between the nodes. 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. The data on such a blockchain can be public or internal to these node participants. Distributed in a partial sense

highlights and pain points: collaborative blockchain can achieve a good connection between nodes, only need a little cost to maintain operation, provide rapid transaction processing and low transaction costs, has good scalability (but the scalability will decline with the increase of nodes), and data can have certain privacy. Developers have the ability to change the protocol under the consensus. There is no problem with bitcoin hard fork, but it also means that everyone can tamper with the data together under the consensus. Collaborative blockchain also means that the application scope of this blockchain will not be too wide, lacking the network propagation effect of bitcoin

private blockchain

example: Eris instries. The participating nodes are only users themselves, and the access and use of data have strict authority management. Most of the blockchain technologies recently announced by some financial institutions for internal use are vague, but they are probably all within this scope

highlights and pain points: private blockchain is actually a confusing term. Such a system is nothing more than a shared database in the traditional sense. Merkle tree and other methods are used to try to show that the data in it is verifiable. There are already mature solutions for such databases, and Merkle tree is only one of many mature solutions. It's easy for these projects to be "like eggs". Because the user has the final say, the data inside can not be changed, and there is not much protection for the third party. Therefore, many private blockchains exist by attaching to bitcoin, such as recording system snapshots to bitcoin regularly

6. The bifurcation of Ethereum Constantinople is about to begin. Many people are curious about this bifurcation and are not sure whether they need to be prepared in advance
to put it simply: if you are only the holder of eth, you don't need to make any preparation for this upgrade.

7. At 21:00 on May 15, BCH upgraded hard fork when UNIX time stamp was 1557921600, allowing segwit (isolation witness) to recover and add Schnorr Signature. BCH can be traded in Chinese currency

8.

About dragonex dragon token

1, basic introction

Dragon token (DT) is a token issued by dragonex based on Ethereum erc20 standard, and each dragon token stored on the platform has the right of project dividend

every day, the transaction commission income of dragonex project will be distributed to all dragon coin holders according to the holding proportion of dragon coin

2. Mining method

longcoin can not be obtained through ICO or pre excavation

all dragon coins can only be generated in the form of "mining", and the only way of mining is to trade on the platform“ Miners (i.e. platform users) contribute to the platform through trading behavior, and the platform issues dragon coins to miners as rewards

the total number of dragon coins issued was 37339500, and promised never to be issued

3. Release rules of dragon coin

Dragon coin is a token based on Ethereum smart contract. Since the launch of Genesis, the smart contract will be released for a total of 3650 times, with an interval of 24 hours and a cycle of 365 times

in the first cycle, 51200 dragon coins will be released each time; The yield of each cycle will be 50% lower than that of the previous cycle

4. Longcoin distribution mechanism

the platform will make statistics on the mining situation of "miners" every day, and the statistical cycle is 0:00:00-23:59:59 on that day; Each time the smart contract releases the Dragon coin, the platform will allocate the new dragon coin to the corresponding "miner" account on the next day according to the statistical data

"miners" dig out dragon coins through trading behavior, but the excavated dragon coins are not 100% owned by miners, among which:

① "miners" get 30% dragon coin reward and

② market brokers get 20% dragon coin reward Market broker: if miner a uses the invitation link of user B when registering, then B is the market broker of user a)

③ dragonex project party gets 10% block dragon coin Award (frozen for one year: for project marketing)

(4) dragonex project party gets 40% block longcoin Award (permanently frozen: used for platform technology research and development, talent introction, project operation, buy back longcoin and destroy)

note: Singapore standard time (UTC / GMT + 08:00)

5. Longcoin dividend mechanism:

① 100% of the daily platform revenue will be distributed to longcoin holders according to the proportion of longcoin holdings

② the platform will take a snapshot of the balance of dragon coin holders at 23:59:59 every day. Since the Dragon coin g up on the same day will arrive the next day, the user can share the Dragon coin on the same day = snapshot data + dragon coin g up on the same day. Dividends will be paid the next day, in the form of usdt to each holder's account

③ dividend formula:

project party's income to be paid dividends = transaction fees + other income of the project

dividend income of currency holding users =

income to be paid dividends * [number of indivial dragon coins held / (number of issued dragon coins - number of destroyed dragon coins)]

6. Online time of dragon coins

Dragon coins began to "mine" and calculate dividends from November 2, 2017

e to the fact that Longyuan is still in the development stage, it can not be released to miners and market brokers. However, the project side will record the data of everyone, and after the development of longcoin is completed, the longcoin and dividends e to everyone will be distributed to the account

longcoin is expected to be developed before November 25, 2017, and will be traded online on dragonex platform. The specific online transaction time will be subject to the official announcement later

9. 1、 Similarity

distributed
git ensures that each code warehouse maintains a complete project library locally, not just the branch in which it works and its own submission history. At the same time, it also keeps all the snapshot and index information after the latest pull

on the blockchain, each node keeps a complete database locally, not just its own transaction information

traceability
in Git commit chain, each commit object contains a parent object (the object of the last commit, except the first commit), which can trace all the previous records

on the blockchain, each block contains the index of the previous block (except the genesis block), which can trace all valid transactions before<

tamper proof
in Git's commit chain, each object itself calculates a checksum before storing, and then references it with a checksum. Once modified, the checksums will not be correct, which means that it is impossible to change the contents of any file or directory without git's knowledge< The mechanism used by git to calculate the checksums is called SHA-1 hash. This is a string composed of 40 hexadecimal characters (0-9 and A-F), which is calculated based on the content or directory structure of the file in GIT. SHA-1 hash looks like this:



in the blockchain, each block contains the last block ID, and this block ID has two SHA-256 hashes, which are calculated based on the block content. Once the content is modified, the hash will change, which is inconsistent with the chain of other nodes and cannot be added to the longest chain, so the content cannot be tampered with< 2. Difference

collective consensus and central node will: 1 - blockchain merges based on collective consensus (POW / POS) to form the longest chain, which is the main chain

2 - in Git system, when multi node cooperation is carried out through the warehouse hosting platform, it is the manager of the platform project who controls the power of merge, which reflects the will of the central node<

cryptography
1 - in bitcoin blockchain, cryptography mainly uses the following methods

in the whole system of bitcoin blockchain, a large number of public encryption algorithms are used, such as Merkle tree hash number algorithm, elliptic curve algorithm, hash algorithm, symmetric encryption algorithm and some coding algorithms. The functions of various algorithms in bitcoin blockchain are as follows:

A) hash algorithm

the two hash functions used in bitcoin system are: 1. SHA-256, which is mainly used to complete pow (proof of workload) calculation; 2. Ripemd160, mainly used to generate bitcoin address

b) Merkle hash tree

binary tree or multi tree based on hash value. In the computer field, Merkle tree is mostly used for integrity verification. In the distributed environment, integrity verification can greatly rece the complexity of data transmission and calculation<

C) elliptic curve algorithm

in bitcoin, the public key cryptography algorithm based on secp256k1 elliptic curve mathematics is used for signature and verification. On the one hand, it can ensure that the user's account is not replaced by an impostor, on the other hand, it can ensure that the user can not deny the signed transaction. The private key is used to sign the transaction information, and the user's public key is used to verify the signature. If the verification is passed, the transaction information will be recorded and the transaction will be completed

d) symmetric encryption algorithm

the official bitcoin client uses AES (symmetric block cipher algorithm) to encrypt the wallet file. After the user sets the password, the private key of the wallet is encrypted by the user set password through AES to ensure the security of the private key of the client

e) base58 encoding

base58 is a unique encoding method used in bitcoin. It is mainly used to generate the wallet address of bitcoin, which is similar to the permutation algorithm mechanism in classical cryptography. Its purpose is to increase the readability of bitcoin and change the binary hash value into the address we see

2 - git: SSH key is mainly used for remote login verification, SHA-1 is used for code content checking sum<

SSH is the abbreviation of secure shell, developed by IETF's network working group. It is a protocol designed to provide security for remote login sessions and other network services. SSH protocol can effectively prevent information leakage in the process of remote management< The process of SSH transmission is as follows: (1) the remote host receives the user's login request and sends its public key to the user 2) The user uses the public key to encrypt the login password and send it back 3) The remote host uses its own private key to decrypt the login password. If the password is correct, the user is allowed to log in.