2019 年算是Oracle 爆发的一年，为什么这样说呢？因为从去年至今仅有少数的竞争币在市场中有亮眼的表现，头部交易所的平台币因有IEO 需求后币价节节攀升，另外一个则是2017 年发起ICO 的项目Chainlink，随着今年主网上线以及重磅消息与谷歌云的BigQuery 合作，无论是币价与技术皆获市场认可，也让大家开始关注到「Oracle」，究竟「Oracle」是什么？又在区块链上扮演什么样的角色?

智能合约的应用发展

区块链在近几年的发展上，最具突破性的代表就是以太坊的智能合约，它让许多新创公司能透过ICO 跨国界的融币、发行自己的ERC20 代币，也实现了在区块链上也能玩养猫的Dapp 游戏，而最令人吒舌的是去中心化资金盘的Fomo3D 游戏，造成了币圈一时的轰动，但这一切只停留在「链上的世界」 ，都还不需用到区块链以外的数据。如果区块链要走到商用可能或支援更多应用场景，那就少不了「Oracle」，这也是为什么今年能看见许多区块链项目相继宣布与Chainlink 合作。

Chainlink 的合作伙伴，一张图列不完

Oracle 是什么？

网络上有许多文章将区块链中的Oracle 翻译为神谕、预言机，而区块链中的Oracle并不是美国的甲骨文软件公司， 而是指一个能够提供外部的真实数据给区块链的数据库，如果区块链是蝙蝠侠，那Oracle 就是他最信赖的阿福。(以下Oracle 统称为预言机)

智能合约与中心化数据库

想起某年与台北以太坊某开发者交流时所学习到的知识，他表示：其实智能合约不够智能，它只是一串代码，其实就是Digital Contract ，可以这么理解「 智能合约会在条件满足的情况下，自动执行开发者的指令」，这件事情在过去大多在区块链上实现并不难，因为玩DAPP 游戏或发币，都不需要真实世界的数据来执行游戏，如果真的需要区块链以外的数据，那就用Oraclize 或是自己写一个API 为合约去获取外部的数据，但假设今天的合约价值非常昂贵，有黑客企图盗取合约内的资产，但因智能合约已经在链上，所以是不可窜改的，但他可以透过窜改给予合约的数据源，也就是合约所需的内容，因为数据内容不在区块链上，如果攻击外部数据的成本是低于合约价值，那窜改数据源是可行的！如果黑客成功攻击了合约获取内容的「数据源」，而遭窜改的数据input 进智能合约读取并且执行，黑客便能成功窃取合约资产。

分散式预言机— 区块链的中间件

智能合约只是代码，并没有主观意识去判别数据的真实性，只要输入的数据能够满足合约条件，合约都会自动执行，所以真实的数据与数据源对于区块链世界来说非常重要，而分散式预言机就是将链下的数据做一次共识，并结合代币激励机制，让社群都能够参与在节点​​中，透过分散式的网络来为智能合约提供真实数据，让智能合约有多个数据库可选，同时也避免掉中心化数据库的单点故障或遭骇客攻击的可能性。

Band Protocol — 区块链数据治理

Band Protocol 是币安下一期的IEO 项目，也是币安IEO 项目中第一个跟预言机有关的项目，其实跟Chainlink 要做的很类似。Band Protocol 透过优化代币数据来源(TCD)，像DPOS 的机制，让持币者票选出数据提供者，而数据提供者将获得大部分的收益，当然参与投票的持币者也能根据质押的相对比例获得代币奖励; Band Protocol 开发了数据治理平台与CoinHatcher (去中心化新闻平台)，目前皆在测试网上运作，在Band Protocol 的数据治理平台上四种可提供给Dapp 的数据，分别为：网站内容、财务数据、运动赛事数据、彩卷数据，仅进去看分别能看到目前有三个节点再提供数据，用户在未来可以将Band 代币兑换成不同领域的Token 来当节点或是投票，Band Protocl 在2020 年主网上线后，将支援所有公链连结所有开放的API，不需依赖中心化机构也可安全地使用互联网的数据。

Band Protocol官网：https://bandprotocol.com/
Band Protocol白皮书：https://bandprotocol.com/whitepaper-v3.0.1-cn.pdf
Band Protocol电报：https://t.me/joinchat/E48nA06UIBFmNsE9OaDusQ
币安研究报告：https://info.binance.com/en/research/BAND-2019-09-06.html

结语

预言机是区块链与现实世界的桥梁，有许多公有链在开发过程时都有考虑到这点，但又要再去做一个分散式的数据库对于团段来说又是一项浩大的工程，因此能看到许多项目在今年与Chainlink合作，就是因为省去了另外再开发预言机的时间与成本，那Band Protocol 的出现会不会对Chainlink 造成威胁？其实不尽然，这就只是让数据需求方多了一个选择，只要预言机所提供的数据是正确并且底层协议的安全性足够，开发者都能自行选择要用哪一家预言机的数据，就像是麦当劳与肯德基都会有自己的市场，并不会因为麦当劳的快乐儿童餐附赠玩具，然后肯德基就丧失掉全部的市场份额！未来，在WEB3.0 的世界里一定会有更多类似的项目出现，而用户都能够选择一个适合自己的入口，来使用区块链的商品与服务。

2019 is considered a breakout year for Oracle. Why do you say this? Because only a few alternative coins have performed well in the market since last year. The platform coins of the leading exchanges have been rising in price due to IEO demand. The other one is Chainlink, an ICO project launched in 2017. Subsequently, With the launch of the mainnet this year and the big news of cooperation with Google Cloud's BigQuery, both the currency price and the technology have been recognized by the market, and everyone has begun to pay attention to "Oracle". What exactly is "Oracle"? What role does it play in the blockchain?

Application and development of smart contracts

In the development of blockchain in recent years, the most breakthrough representative is the smart contract of Ethereum, which allows Many new companies can raise money across borders through ICO and issue their own ERC20 tokens. They can also play cat-raising Dapp games on the blockchain. The most astonishing thing is decentralized funds. The Fomo3D game on the market caused a sensation in the currency circle, but all this only stayed in the "world on the chain" and did not require the use of data outside the blockchain. If the blockchain is going to be commercially possible or support more application scenarios, then "Oracle" is indispensable. This is why we can see many blockchain projects announcing cooperation with Chainlink this year.

The list of Chainlink partners is endless

What is Oracle?

There are many articles on the Internet that translate the Oracle in the blockchain into oracles and oracles. The Oracle in the blockchain is not the Oracle software company in the United States, but refers to a company that can provide external real data to the region. Blockchain database, if the blockchain is Batman, then Oracle is his most trusted Afu. (Oracles are collectively referred to as oracles below)

Smart contracts and centralized databases

Recalling what he learned when communicating with a developer of Ethereum in Taipei one year ago, he said: In fact, smart contracts are not smart enough; A string of code is actually a Digital Contract. It can be understood this way: "The smart contract will automatically execute the developer's instructions when the conditions are met." In the past, it was mostly not difficult to implement on the blockchain, because playing DAPP Neither games nor currency issuance require real-world data to execute the game. If you really need data outside of the blockchain, then use Oraclize or write an API yourself to obtain external data for the contract, but assuming that today’s contract The value is very expensive. Some hackers try to steal the assets in the contract. However, because the smart contract is already on the chain, it cannot be tampered with. However, he can tamper with the data source given to the contract, which is the content required by the contract, because The data content is not on the blockchain. If the cost of attacking external data is lower than the contract value, then tampering with the data source is feasible! If a hacker successfully attacks the contract to obtain the content "Data source", and the tampered data input is read and executed in the smart contract, and the hacker can successfully steal the contract assets.

Decentralized oracle - the middleware of the blockchain

Smart contracts are just codes, and there is no subjective consciousness to judge the authenticity of the data. As long as the input data can meet the contract conditions, the contract will be automatically executed, so it is true The data and data sources are very important to the blockchain world, and the decentralized oracle is to make a consensus on the data off the chain, and combine it with the token incentive mechanism to allow the community to participate in the nodes and transparently A decentralized network is used to provide real data for smart contracts, allowing smart contracts to have multiple databases to choose from, while also avoiding the possibility of single points of failure in centralized databases or being attacked by hackers.

Band Protocol — Blockchain Data Governance

Band Protocol is the next IEO project of Binance. It is also the first project related to oracles in the Binance IEO project. In fact, it has a lot to do with Chainlink. similar. Band Protocol optimizes the token data source (TCD), like a DPOS mechanism, to allow currency holders to vote for data providers, and the data providers will receive most of the revenue. Of course, currency holders who participate in the voting can also vote based on their pledges. The relative proportion of token rewards; Band Protocol has developed a data governance platform and CoinHatcher (decentralized news platform), both of which are currently operating on the test network. There are four types of data that can be provided to Dapps on Band Protocol’s data governance platform, respectively. It is: website content, financial data, sports event data, lottery data. If you just go in and look at it, you can see that there are currently three nodes that provide data. In the future, users can exchange Band tokens for Tokens in different fields to serve as nodes or vote. After the mainnet is launched in 2020, Band Protocl will support all public chains and all open APIs, and can safely use Internet data without relying on centralized institutions.

Band Protocol official website: https://bandprotocol.com/
Band Protocol white paper: https://bandprotocol.com/whitepaper-v3.0.1-cn.pdf
Band Protocol Telegram: https://t.me/joinchat/E48nA06UIBFmNsE9OaDusQ
Binance Research Report: https://info.binance.com/en/research/BAND-2019-09-06.html

Conclusion

Oracles are the bridge between blockchain and the real world. There are many public chains under development.This was taken into consideration during the development process, but having to build a decentralized database is also a huge project for the group. Therefore, we can see many projects cooperating with Chainlink this year, just because it saves In addition to the time and cost of developing oracles, will the emergence of Band Protocol pose a threat to Chainlink? In fact, not necessarily. This just gives data demanders one more choice. As long as the data provided by the oracle is correct and the security of the underlying protocol is sufficient, developers can choose which oracle to use, just like Both McDonald's and KFC will have their own markets, and KFC will not lose all its market share just because McDonald's Happy Meals come with toys! In the future, there will definitely be more similar projects in the WEB3.0 world, and users can choose an entrance that suits them to use blockchain goods and services.