浅谈区块链技术中的智能合约

智能合约（smart contract）的定义最早由法律学者Nick Szabo在1995年提出，其定义为：“一个智能合约是一套以数字形式定义的承诺（promise），包括合约参与方可以在上面执行这些承诺的协议。”即智能合约是一个在计算机系统上，当一定条件被满足的情况下，可以被自动执行的合约。

The definition of smart contracts (smart contract) was first proposed by the jurist Nick Szabo in 1995 and defined it as: “A smart contract is a set of numerically defined commitments (promise), including the agreement on which the parties to the contract can implement those commitments.” In other words, an intelligent contract is a contract on a computer system that can be automatically executed when certain conditions are met.

现代社会中智能合约最典型的例子就是银行信用卡的自动还款服务，在具体的时间（信用卡还款日），当还款条件被满足时（信用卡有消费账单且还款储蓄卡余额比信用卡还款金额要多），计算机系统会自动完成这笔交易（从储蓄卡上自动扣减信用卡消费金额还款）。

The most typical example of an intelligent contract in a modern society is the automatic repayment service of bank credit cards, which will automatically be completed by the computer system at a specific time (day of credit card repayment), when the terms of repayment have been met (credit card has consumer bills and the balance of the repayment card is higher than the amount of credit card repayment).

智能合约本质上是一段写入区块链网络的可执行代码，参与方通过在合约宿主平台上安装合约，通过区块链技术手段致力于合约的执行，以计算机指令的方式实现了传统合约的自动化处理。

Smart contracts are essentially an executable code for the network of blocks that are automated by means of computer directives through the installation of contracts on the host platform, the implementation of contracts through the technical means of block chains.

智能合约的特点

Features of Smart Contracts

自动化

Automation

如果说一个智能合同是自动化的，不是指它自动被执行，因为在实践中有些法律协议执行可能不是自动的，需要人工输入和控制。然而，要实现“智能合约”，需要执行的某些部分必须是自动的，否则这个合同就不智能。自动化通常意味着由一个或多个计算机执行，它是“电子手段”的代名词。一个自动运用智能合约的典型例子，就是Ian Grigg设计的由条文、参数和代码组成的李嘉图合约（Ricardian Contract） 。李嘉图合约可以被定义为一个简单的文档：由发起人提供给持有者的协议；持有者享有一定的权利，由发起人管理；容易被人理解；是一种可读的程序（解析得像一个数据库）；有数字签名；携带密钥和服务信息；有一个独特的安全的标识符。

If an intelligent contract is automated, it does not mean that it is executed automatically, because in practice some legal agreements may not be self-executing and require manual input and control. However, to achieve a “smart contract”, certain parts of the contract that need to be executed must be automatic, otherwise the contract is not intelligent. Automation usually means that it is executed by one or more computers, and it is a term for “electronic means”. A typical example of an automated application of an intelligent contract is the Li Gato contract, designed by Ian Grigg, consisting of articles, parameters and codes. The Li Gato contract can be defined as a simple document: an agreement provided by the initiator to the holder; the holder has certain rights, administered by the originator; it is easy to understand; it is a readable program (discovering a database); it has a digital signature; it carries a key and service information; and it has a unique secure identifier.

可执行性

Enforceability

智能合约代码和智能法律合约的最大不同是哪些要素需要强制执行。对于智能合约代码，最关键的要求是代码必须执行成功和按时准确地完成。对于智能法律合约，事情可能复杂得多。通常，法律合同将有大量的权利和义务添加到协议各方并具有法律效力。这些通常在表达上比较复杂、用词敏感，法律条文涉及的可能不只是个人行为。虽然某些研究机构正在推行基于区块链技术的智能合约防篡改代码，但其实最好的办法是将智能合约放在由防篡改网络序列构成的执行体系当中，也就是需要建立一个智能合约模板。

The biggest difference between smart contract codes and smart legal contracts is what needs to be enforced. The most critical requirement for smart contract codes is that the code must be executed successfully and accurately on time.