But what are they and what problems do they solve?

但是它們到底是甚麼，又解決了甚麼問題呢?

The term “smart contract” was first used by Nick Szabo in 1997, long before Bitcoin

早在比特幣之前，Nick Szabo就於1997年提出"智能合同"的說法。

was created.

早在比特幣之前，Nick Szabo就於1997年提出"智能合同"的說法。

He is a computer scientist, law scholar and cryptographer so I'll spare you his exact

他同時是個計算機科學家、法律學者與密碼學家，所以將不會在此逐字逐句地說明他的繁複字句。

words.

他同時是個計算機科學家、法律學者與密碼學家，所以將不會在此逐字逐句地說明他的繁複字句。

But in simple terms: he wanted to use a distributed ledger to store contracts.

簡單的來說，他想透過分布式帳本達到儲存合同的目的。

Now, smart contracts are just like contracts in the real world.

而現在，智能合同就與現實生活中的合同一般無異。

The only difference is that they are completely digital.

兩者之間的唯一不同在於它們是完全由數字所構成。

In fact a smart contract is actually a tiny computer program that is stored inside a blockchain.

事實上智能合同是一個儲存在小型電腦程序中的區塊練。

Let's take a look at an example to understand how smart contracts work.

舉個例子讓你明白智能合同的運作方式。

You probably are familiar with Kickstarter, the large fundraising platform.

你應該對一個名為"Kickstarter"的籌款平台感到熟悉。

Product teams can go to Kickstarter, create a project, set a funding goal and start collecting

製造團隊可以在Kickstarter，設立一個項目和資助目標並等待喜歡這個項目的人來投資。

money from others who believe in the idea.

製造團隊可以在Kickstarter，設立一個項目和資助目標並等待喜歡這個項目的人來投資。

Kickstarter is essentially a third party that sits between product teams and supporters.

Kickstarter便是一個第三方坐落於製造團隊與資助者之間擔任溝通的角色。

This means that both of them need to trust Kickstarter to handle their money correctly.

這意味著雙方必須委託Kickstarter妥善處理流通的錢。

If the project gets successfully funded, the project team expects Kickstarter to give them

如果這個項目成功的被投資了，製造團隊會期望Kickstarter將錢轉交到他們手中。

the money.

如果這個項目成功的被投資了，製造團隊會期望Kickstarter將錢轉交到他們手中。

On the other hand, supporters want their money to go to the project if it was funded or to

而另一方面，資助者會希望它們的錢會被成功的交至製造團隊手上

get a refund when it hasn't reached its goals.

或是在他們沒達到目標時得到償還。

Both the product team and its supports have to trust Kickstarter.

製造團隊與資助者都必須依附Kickstarter。

But with smart contracts we can build a similar system that doesn't require a third-party

但是當透過智能合同我們可以打造一個類似的系統而不需要像Kickstarter的第三方介入。

like Kickstarter.

但是當透過智能合同我們可以打造一個類似的系統而不需要像Kickstarter的第三方介入。

So let's create a smart contract for this!

所以，讓我們為此建立智能合同吧!

We can program the smart contract so that it holds all the received funds until a certain

我們可以訂定一項智能合同並讓它握有收到的資助金直到一個特定目標被完成。

goal is reached.

我們可以訂定一項智能合同並讓它握有收到的資助金直到一個特定目標被完成。

The supporters of a project can now transfer their money to the smart contract.

如此一來，一個項目的的資助者可以將錢投入到智能合同。

If the project gets fully funded, the contract automatically passes the money to the creator

如果這個項目被完全地資助了，合同就會自動將錢傳遞給該項目的製造團隊。

of the project.

如果這個項目被完全地資助了，合同就會自動將錢傳遞給該項目的製造團隊。

And if the project fails to meet the goal, the money automatically goes back to the supporters.

而如果項目沒有達到目標，錢也會自動回到資助者身上。

Pretty awesome right?

挺棒的是吧?

And because smart contracts are stored on a blockchain, everything is completely distributed.

而因為智能合同是儲存在一個區塊鏈的，所有的東西是完全分布式的。

With this technique, no one is in control of the money.

透過科技，錢不會落到人和一個人的掌控中。

But wait a minute!

但是等一下!

Why should we trust a smart contract?

我們為甚麼要憑信智能合同?

Well because smart contracts are stored on a blockchain, they inherit some interesting

其實是因為智能合同式被儲存在區塊鏈中的，這使他們有一些有趣的性質。

properties.

其實是因為智能合同式被儲存在區塊鏈中的，這使他們有一些有趣的性質。

They are immutable and they are distributed.

它們是一成不變且分布式的。

Being immutable means that once a smart contract is created, it can never be changed again.

這表示一旦一份智能合同被訂定後，就不可能可以更改了。

So no one can go behind your back and tamper with the code of your contract.

所以沒有人可以偷偷的竄改合同的內容。

And being distributed means that the output of your contract is validated by everyone

而分布式則是代表你所擬出的智能合同將會被所有網路上的電腦驗證過。

on the network.

而分布式則是代表你所擬出的智能合同將會被所有網路上的電腦驗證過。

So a single person cannot force the contract to release the funds because other people

所以單個人不能強迫合同釋出資助金

on the network will spot this attempt and mark it as invalid.

因為其他網路上的電腦會式別出紀錄並使程序無效化。

Tampering with smart contracts becomes almost impossible.

算改智能合同的機率將微乎其微。

Smart contracts can be applied to many different things, not just on crowdfunding.

智能合同可以被應用在各種方面，不只集資。

Banks could use it to issue loans or to offer automatic payments.

銀行可以用它來借出貸款或提供自動支付的功能。

Insurance companies could use it to process certain claims.

保險公司可以用它來處理索賠問題。

Postal companies could use it for payment on delivery, and so on and so on…

郵政公司可以用它收取貨物費用，等等......。

So, now you might wonder where and how you can use smart contracts.

所以現在你應該會明白智能合同的用處與用法了。

Right now there are a handful of blockchains who support smart contracts, but the biggest

現在有少數的區塊鏈支援智能合同，其中最大的是Ethereum。

one is Ethereum.

現在有少數的區塊鏈支援智能合同，其中最大的是Ethereum。

It was was specifically created and designed to support smart contracts.

它是特別設計用來支援智能合同的。

They can be programmed in a special programming language called Solidity.

它們是由名為Solidity的程式語言編程的。

This language was specifically created for Ethereum and uses a syntax that resembles

這款語言是特地為Ethereum而創造的，而它酷似Javascript。

Javascript.

這款語言是特地為Ethereum而創造的，而它酷似Javascript。

Its worth noting that Bitcoin also has support for smart contracts although it's a lot

值得一提的是，比特幣也可以支援智能合同，

more limited compared to Ethereum.

雖然與Ethereum相比它的限制多了許多。

So now you know what smart contracts are and what problem they solve.

所以現在你知道，何為智能合同和它們能解決的問題了。

I hope you enjoyed this video and if you did, hit the like button and get subscribed.

希望你喜歡這部影片請點讚並訂閱唷。

And as always: thank you very much for watching! #youtube/simply-explained

最後，非常感謝你的收看!