比特币的智能合约比特币网络上可以运行智能合约

网络投稿

2022-04-24 06:15:08

❶ 比特币是如何完成升级和迭代的

如今这个互联网时代，很多软件采取的都是先开发一个简化版，然后经过不停的迭代，数据多了就增加存储器，性能不够了就升级服务器。总之就是一切跟着需求来，总能解决各种各样的问题。然而，你可曾想过，当这些问题进入到区块链的场景，可能就没那么容易了。

闪电网络实际通过微支付的通道，将交易剥离出比特币区块链来进行，而且剥离主链的交易次数是无限的，这从根本上解决了大量交易都放在比特币主链上进行，从而大大提高了交易的效率。

多链：区块链应用的扩展交互

现在我们看到的很多区块链基础技术构架都是单链的形态。但在现实社会各个产业价值网络中，多链结构的技术才更符合复杂价值逻辑的实际应用，各行各业或者说各个领域都用可能针对不同的业务来构造一条链，这些平行的链之间就会存在数据交互的需求，即便实在同一个业务场景下，也有可能构建一组共同配合工作的链来完成复杂的业务逻辑。此时就会需要通过一个专门的接口来实现互联，大家共同遵循同一个规则，各种不同的链只要针对接口规范来进行开发，就可以进行互联，从而为自身的发展实现了更多可能。

❷ 如何理解区块链的智能合约

智能合约”（smart contract）这个术语至少可以追溯到1995年，是由多产的跨领域法律学者尼克·萨博（Nick Szabo）提出来的。他在发表在自己的网站的几篇文章中提到了智能合约的理念。他的定义如下：

“一个智能合约是一套以数字形式定义的承诺（promises），包括合约参与方可以在上面执行这些承诺的协议。”

让我们更加详细地探讨他的定义的意思。

承诺

一套承诺指的是合约参与方同意的（经常是相互的）权利和义务。这些承诺定义了合约的本质和目的。以一个销售合约为典型例子。卖家承诺发送货物，买家承诺支付合理的货款。

数字形式

数字形式意味着合约不得不写入计算机可读的代码中。这是必须的，因为只要参与方达成协定，智能合约建立的权利和义务，是由一台计算机或者计算机网络执行的。

更进一步地说明：

（1）达成协定

智能合约的参与方什么时候达成协定呢？答案取决于特定的智能合约实施。一般而言，当参与方通过在合约宿主平台上安装合约，致力于合约的执行时，合约就被发现了。

（2）合约执行

“执行”的真正意思也依赖于实施。一般而言，执行意味着通过技术手段积极实施。

（3）计算机可读的代码

另外，合约需要的特定“数字形式”非常依赖于参与方同意使用的协议。

协议

协议是技术实现（technical implementation），在这个基础上，合约承诺被实现，或者合约承诺实现被记录下来。选择哪个协议取决于许多因素，最重要的因素是在合约履行期间，被交易资产的本质。

再次以销售合约为例。假设，参与方同意货款以比特币支付。选择的协议很明显将会是比特币协议，在此协议上，智能合约被实施。因此，合约必须要用到的“数字形式”就是比特币脚本语言。比特币脚本语言是一种非图灵完备的、命令式的、基于栈的编程语言，类似于Forth。

智能合约

链乔教育在线旗下学硕创新区块链技术工作站是中国教育部学校规划建设发展中心开展的“智慧学习工场2020-学硕创新工作站 ”唯一获准的“区块链技术专业”试点工作站。专业站立足为学生提供多样化成长路径，推进专业学位研究生产学研结合培养模式改革，构建应用型、复合型人才培养体系。

❸ 什么是智能合约

智能合约概念可以概括为: 一段代码 (智能合约)，被部署在分享的、复制的账本上，它可以维持自己的状态，控制自己的资产和对接收到的外界信息或者资产进行回应。智能合约，简而言之就是一套以数字形式定义的承诺，包括合约参与方可以在上面执行这些承诺的协议。

❹ 智能合约是什么

智能合约"(smart contract)这个术语至少可以追溯到1995年，是由多产的跨领域法律学者尼克·萨博(Nick Szabo)提出来的。他在发表在自己的网站的几篇文章中提到了智能合约的理念。他的定义如下:
"一个智能合约是一套以数字形式定义的承诺(promises)，包括合约参与方可以在上面执行这些承诺的协议。"
让我们更加详细地探讨他的定义的意思。
承诺
一套承诺指的是合约参与方同意的(经常是相互的)权利和义务。这些承诺定义了合约的本质和目的。以一个销售合约为典型例子。卖家承诺发送货物，买家承诺支付合理的货款。
数字形式
数字形式意味着合约不得不写入计算机可读的代码中。这是必须的，因为只要参与方达成协定，智能合约建立的权利和义务，是由一台计算机或者计算机网络执行的。
更进一步地说明:
(1)达成协定
智能合约的参与方什么时候达成协定呢?答案取决于特定的智能合约实施。一般而言，当参与方通过在合约宿主平台上安装合约，致力于合约的执行时，合约就被发现了。
(2)合约执行
"执行"的真正意思也依赖于实施。一般而言，执行意味着通过技术手段积极实施。
(3)计算机可读的代码
另外，合约需要的特定"数字形式"非常依赖于参与方同意使用的协议。
协议
协议是技术实现(technical implementation)，在这个基础上，合约承诺被实现，或者合约承诺实现被记录下来。选择哪个协议取决于许多因素，最重要的因素是在合约履行期间，被交易资产的本质。
再次以销售合约为例。假设，参与方同意货款以比特币支付。选择的协议很明显将会是比特币协议，在此协议上，智能合约被实施。因此，合约必须要用到的"数字形式"就是比特币脚本语言。比特币脚本语言是一种非图灵完备的、命令式的、基于栈的编程语言，类似于Forth。

❺ sfch是什么币

一、sfch是什么币
没有sfch这种币，现在市面上有sfc这种币。
Solarflarecoin也叫SFC币，它是基于Scrypt散列算法的工作证明加密货币，它有18%的预支作为发展基金。Solarflarecoin（SFC币）发行总量为14，083，450 SFC，目前上架2家交易平台分别为：C网-Cryptopia和CoinExchange。

二、主流加密货币
1、BitCoin 比特币
加密货币/虚拟货币的开山祖师爷，由身份至今未明的中本聪(Satoshi Nakamoto)先生于2008年11月发表比特币白皮书，比特币及后于2009年1月正式上线，成为全世界第一款并且最成功的加密货币。上限为2100万个，所有BitCoin将于2140年发掘完成，之后不会再有新比特币出现。很多其他加密货币都是从比特币的区块链分裂出去，例如LiteCoin，BitCoin Cash。

2、Ether 以太坊
2013年由Vitalik Buterin提出，是现时市值第二高的加密货币。Vitalik想建立一个基于分散式区块链的平台运行Smart Contract(智能合约)，这个平台称为Ethereum(以太坊)。Ether是在Ethereum平台上运行程序时缴交费用的媒界，与BitCoin希望成为日常使用货币的定位有很大分别，另外几个重大分别包括:Ether的发行量是无上限的，Ether采用的是PoS (Proof-of-Stake)，而BitCoin采用的是PoW (Proof-of-Work)。

3、LiteCoin 莱特币
2011年7月由前Google员工Charlie Lee从BitCoin的Blockchain分叉出去，与BitCoin仅有两点不同:
1. BitCoin每10分钟生成下一个区块，LiteCoin只需2.5分钟
2. BitCoin用SHA256作为Hash function，LiteCoin使用Scrypt (一种Memory hard function)，目的是令普通人也可以用家用电脑参与掘矿获利，打破BitCoin现时由ASIC/FPGA垄断的局面。

4、Monero 门罗币
完全为Privacy而创造的加密货币，将Bitcoin的匿名性推到极致，连交易额和目的地址都没有公开到网络。理论上没有上限，实际上当第1千8百30万个Monero被掘出后，每分钟只有0.3个新增Monero。2017年WannaCry 病毒大规模攻击Windows用户，锁上电脑所有文件并以此勒索用家BitCoin，后来有调查发现黑客之后将BitCoin兑换为Monero，此后这笔款项便无法被跟纵。

5、Tether (USDT) 泰达币
与所有其他加密货币不同，USDT与美金的值是挂钓的，1USDT应该刚刚好等于1USD，虽然现实上往往有几个%的差距。只有Kraken exchange能将USDT兑换成USD 根据Tether白皮书，每一个USDT背后都有一个USD支持，而这大笔美金现金是存于一间香港公司Tether Limited. 使用USDT而非USD有几个好处: 节省汇款到各大加密货币交易所的手续费; 节省存款入交易所的时间等。

6、DogeCoin 狗狗币
本来只是玩票性质而创造出来的加密货币，与Litecoin一样使用Scrypt，但数量没有上限。狗狗币的主要用途为慈善筹款，例如2014年冬季奥运会期间，一支牙买加的有舵雪橇(Bobsleigh)队伍获得冬奥参赛资格，却没有资金出赛，狗狗币社群为该支队伍筹得5万美金赞助他们到俄罗斯索契参加比赛。

❻ 区块链的特征是什么

区块链的特征是：

1、不可篡改

区块链最容易被理解的特性是不可篡改的特性。不可篡改是基于“区块＋链”（block+chain）的独特账本而形成的：存有交易的区块按照时间顺序持续加到链的尾部。要修改一个区块中的数据，就需要重新生成它之后的所有区块。

2、表示价值所需要的唯一性

不管是可互换通证（ERC20），还是不可互换通证（ERC721），又或者是其他提议中的通证标准，以太坊的通证都展示了区块链的一个重要特征：表示价值所需要的唯一性。在数字世界中，最基本单元是比特，比特的根本特性是可复制。但是价值不能被复制，价值必须是唯一的。

3、智能合约

从比特币到以太坊，区块链最大的变化是“智能合约”。比特币系统是专为一种数字货币而设计的，它的UTXO和脚本也可以处理一些复杂的交易，但有很大的局限性。而维塔利克创建了以太坊区块链，他的核心目标都是围绕智能合约展开的：一个图灵完备的脚本语言、一个运行智能合约的虚拟机（EVM），以及后续发展出来的一系列标准化的用于不同类型通证的智能合约等。

4、去中心自组织

区块链的第四大特征是去中心自组织。到目前为止，主要区块链项目的自身组织和运作都与这个特征紧密相关。很多人对区块链项目的理想期待是，它们成为自治运转的一个社区或生态。

5、开放性。

区块链技术基础是开源的，除了交易各方的私有信息被加密外，区块链的数据对所有人开放，任何人都可以通过公开的接口查询区块链数据和开发相关应用，因此整个系统信息高度透明。

❼ 啥叫智能合约

在区块链上运行的程序，通常称为智能合约(Smart Contract)。所以通常会把写区块链程序改称写智能合约。
虽然比特币(Bitcoin)上也能写智能合约，但是比特币所支持的语法仅与交易有关，能做的事情比较有限。
因此目前提到写智能合约，通常指的是支持执行图灵完备程序的以太坊(Ethereum)区块链。

❽ 在区块链中什么是侧链和主链

主链：即正式上线的、独立的区块链网络。可以这样说，区块链的存储数据的实体，一般认为是主链网络本身。比如BTC主网、ETH主网和EOS主网都是主链。

侧链：首先，侧链协议的本质属于一种跨区块链的解决方案。简单的说,通过此方案可以让数据信息在两条区块链之间实现转移。侧链最初的提出是基于实现比特币和其他数字资产在多个区块链间的转移。

通俗来说，侧链就像是一条条通路，将不同的区块链互相连接在一起，以实现区块链的扩展。侧链完全独立于主链，但是这两个账本之间能够“互相操作”，实现交互。

侧链协议——侧链协议是指(以比特币为例)：可以让比特币安全地从比特币主链转移到其他区块链，又可以从其他区块链安全地返回比特币主链的一种协议。这里将比特币换成以太币或者其他区块链也是同样的道理。那请问，我们为什么需要侧链，或者侧链有什么好处呢？

主链缺乏的功能，侧链来提供。

比如比特币网络没有智能合约的功能，但可以通过侧链来实现这一功能。

如果主链的运行效率低下，可以将主链部分功能转移到侧链来实施。

比如主链的转账速度很慢，没有办法满足日常支付需求，我们可以开发闪电网络来作为侧链满足日常的支付。同样是因为性能低下，以太坊没有办法支持大型商业级的DAPP（去中心化应用），可以通过侧链开发来实现。

如果抛开技术上的严谨性，可以采用另外一种更为简单的方式来理解侧链，一切为原来的主网络提供支持或者服务的网络都可以叫做侧链，不用在乎这个侧链是否采用区块链技术。比如：

第三方支付网络（支付宝/微信），可以把银行网络想象成为主链，而第三方支付就是一种侧链。

加密货币交易，把比特币等虚拟货币等自由的网络看成是主链，那交易所可以看成一个侧链。

RSK 和Loom，他们分别是针对比特币和以太坊主链单独开发出来的侧链。

第一种应用，里面的主链和侧链都是中心化的

第二种应用，主链是去中心化，侧链是中心化的

第三种应用，主链是去中心化，侧链也是去中心化随着区块链技术的深入，我们可以看到人类的价值交换活动，会慢慢的从第一种应用逐步过渡到第三种应用。

❾ 比特币支持智能合约吗

不支持比特币只能点对点传输目前

❿ 《区块链技术驱动金融数字货币与智能合约技术》pdf下载在线阅读，求百度网盘云资源

《区块链技术驱动金融》（阿尔文德·纳拉亚南）电子书网盘下载免费在线阅读

资源链接：

链接: https://pan..com/s/1kjXFQI1EYFZ3Yh0hIETszw 提取码: fk9u

书名：区块链技术驱动金融

作者：阿尔文德·纳拉亚南

译者：林华

豆瓣评分：8.2

出版社：中信出版社,中信出版集团

出版年份：2016-8-25

页数：432

内容简介：

从数字货币及智能合约技术层面，解读了区块链技术在金融领域的运用。“如果你正在寻找一本在技术层面解释比特币是如何运作的，并且你有一定计算机科学和编程的基本知识，这本书应该很适合你。”

《区块链：技术驱动金融》回答了一系列关于比特币如何运用区块链技术运作的问题，并且着重讲述了各种技术功能，以及未来会形成的网络。比特币是如何运作的？它因何而与众不同？你的比特币安全吗？比特币用户如何匿名？区块链如何帮助比特币实现没有身份的共识？我们可以在比特币这一平台上创建什么应用程序？加密数字货币可以被监管吗？创建一种新的数字货币将会带来什么样的变化？未来将会如何发展？

读完这本书，你会了解到所有比特币和其他数字货币相关的知识，对区块链技术具备基础性认识，能够区别那些完全虚构的故事。你将会对于需要什么样的安全软件，如何与比特币网络进行交互有了基础概念，也可以将区块链的概念整合应用于自己的项目中。你，将会成为时代的引领者！

作者简介：

阿尔文德·纳拉亚南，普林斯顿大学计算机系副教授，科学家。

约什·贝努，电子前沿基金（Electronic Frontier Foundation）技术员，斯坦福大学博士后。

爱德华·费尔顿，普林斯顿大学计算机科学和公共事务教授，2015年被任命为奥巴马总统的技术顾问。

安德鲁·米勒，马里兰大学计算机科学博士。

史蒂文·戈德费德，普林斯顿大学计算机科学博士。

译者简介：

林华，中国资产证券化研究院院长、中国资产证券化分析网董事长、中国基金行政管理网CEO、兴业银行独立董事。

王勇，光大证券首席风险官。

帅初，唯链科技（vechain）首席技术官，中国区块链开源平台QtumChain的设计者。

蔡凯龙，点石资产管理创始人，厦门抬钱论道资产管理公司执委会主席，互联网金融千人会联合创始人。

许余洁，联合信用评级有限公司研究总监，中国资产证券化研究院首席研究员，西南财经大学特聘研究员。

李耀光，某合资证券公司结构融资总监。

高晓婧，兴业银行总行投资银行部。

洪浩，中泰证券债券与结构金融部。

❶ How Bitcoin completes upgrades and iterations

In today's Internet era, many software first develop a simplified version, and then through continuous iteration, there is more data Just increase the storage, and upgrade the server if the performance is not enough. In short, everything follows the needs and can always solve various problems. However, have you ever thought that when these problems enter the blockchain scenario, it may not be so easy.

The Lightning Network actually separates transactions from the Bitcoin blockchain through micropayment channels, and the number of transactions that can be separated from the main chain is unlimited. This is fundamentally It solves the problem that a large number of transactions are carried out on the Bitcoin main chain, thus greatly improving the efficiency of transactions.

Multi-chain: Extended interaction of blockchain applications

Many of the basic technical architectures of blockchains we see now are in the form of single chains. However, in the value network of various industries in real society, the technology of multi-chain structure is more in line with the practical application of complex value logic. All walks of life or various fields use it to construct a chain that may target different businesses. Between these parallel chains There will be a need for data interaction. Even in the same business scenario, it is possible to build a set of chains that work together to complete complex business logic. At this time, a special interface will be needed to achieve interconnection. Everyone follows the same rules. As long as various chains are developed according to the interface specifications, they can be interconnected, thereby realizing more possibilities for their own development.

❷ How to understand smart contracts in blockchain

The term “smart contract” dates back to at least 1995 and was coined by the prolific cross-field legal scholar Nick It was proposed by Nick Szabo. He mentioned the concept of smart contracts in several articles published on his website. His definition is as follows:

“A smart contract is a set of digital Defined promises, including protocols on which contract participants can execute those promises. ”

Let us explore the meaning of his definition in more detail.

Commitments

A set of promises agreed upon by the parties to a contract (often mutually of) rights and obligations. These commitments define the nature and purpose of the contract. Take a sales contract as a typical example. The seller promises to deliver the goods, and the buyer promises to pay a reasonable price.

Digital form

Digital form means that the contract must be written in computer-readable code. This is necessary because as long as the parties reach an agreement, the rights and obligations established by the smart contract are executed by a computer or computer network.

Further explanation:

(1) Reaching an agreement

When do the participants in a smart contract reach an agreement? The answer depends on the specific smart contract implementation . Generally speaking, when a participant installs a contract on the contract host platform,When the contract is installed and committed to its execution, the contract is discovered.

(2) Contract execution

The true meaning of "execution" also depends on implementation. Generally speaking, implementation means active implementation through technical means.

(3) Computer-readable code

In addition, the specific "digital form" required for the contract depends very much on the protocol the parties agree to use.

Agreement

Agreement is a technical implementation, based on which contract commitments are realized or the realization of contract commitments is recorded. Which protocol is chosen depends on many factors, the most important being the nature of the assets being traded during the performance of the contract.

Take the sales contract as an example again. Assume that the parties agree to pay in Bitcoin. The protocol of choice will obviously be the Bitcoin protocol, on which smart contracts are implemented. Therefore, the "digital form" that the contract must use is the Bitcoin script language. The Bitcoin Script Language is a non-Turing complete, imperative, stack-based programming language similar to Forth.

Smart Contract

The Xueshuo Innovation Blockchain Technology Workstation under Lianqiao Education Online is a Chinese education It is the only approved "blockchain technology professional" pilot workstation for the "Smart Learning Workshop 2020-Master's Degree Innovation Workstation" launched by the Ministry of Education's Planning, Construction and Development Center. The professional position is based on providing students with diversified growth paths, promoting the reform of the training model integrating professional degree research, production, and research, and building an applied and compound talent training system.

❸ What is a smart contract?

The concept of smart contract can be summarized as: a piece of code (smart contract), which is deployed on a shared and replicated ledger, and can maintain its own state , control one's own assets and respond to received external information or assets. A smart contract is, simply put, a set of commitments defined in digital form, including an agreement on which contract participants can execute these commitments.

❹ What is a smart contract?

The term "smart contract" dates back to at least 1995 and was coined by the prolific interdisciplinary legal scholar Nick Szabo ). He mentioned the concept of smart contracts in several articles published on his website. His definition is as follows:
"A smart contract is a set of promises defined in digital form. Includes an agreement on which the parties to the contract can execute these commitments. "
Let's explore what his definition means in more detail.
Commitments
A set of commitments refers to the (often mutual) rights and obligations agreed upon by the parties to a contract. These commitments define the essence and purpose of the contract. Taking a sales contract astypical example. The seller promises to deliver the goods and the buyer promises to pay a reasonable price.
Digital form
Digital form means that the contract has to be written in computer-readable code. This is necessary because as long as the parties reach an agreement, the rights and obligations established by the smart contract are executed by a computer or computer network.
Further explanation:
(1) Agreement reached
When do the participants in a smart contract reach an agreement? The answer depends on the specific smart contract implementation. Generally speaking, a contract is discovered when a party commits to its execution by installing the contract on the contract hosting platform.
(2) Contract Execution
The true meaning of "execution" also depends on implementation. Generally speaking, implementation means active implementation through technical means.
(3) Computer-readable code
In addition, the specific "digital form" required for a contract is very dependent on the protocol the parties agree to use.
Agreement
Agreement is a technical implementation, based on which contract commitments are realized or the realization of contract commitments is recorded. Which protocol is chosen depends on many factors, the most important being the nature of the assets being traded during the performance of the contract.
Again, take the sales contract as an example. Assume that the parties agree to pay in Bitcoin. The protocol of choice will obviously be the Bitcoin protocol, on which smart contracts are implemented. Therefore, the "digital form" that the contract must use is the Bitcoin script language. The Bitcoin Script Language is a non-Turing complete, imperative, stack-based programming language similar to Forth.

❺ What currency is sfch

1. What currency is sfch
There is no currency like sfch, but there is a currency like sfc on the market now.
Solarflarecoin, also called SFC coin, is a proof-of-work cryptocurrency based on the Scrypt hash algorithm. It has an 18% advance as a development fund. The total issuance of Solarflarecoin (SFC currency) is 14,083,450 SFC. Currently, it is listed on 2 trading platforms: C Network-Cryptopia and CoinExchange.

2. Mainstream Cryptocurrencies
1. BitCoin Bitcoin
The founder of cryptocurrency/virtual currency was published in November 2008 by Mr. Satoshi Nakamoto, whose identity is still unknown. Bitcoin white paper, Bitcoin was officially launched in January 2009, becoming the world's first and most successful cryptocurrency. The upper limit is 21 million. All Bitcoins will be mined in 2140, and no new Bitcoins will appear after that. a lot ofOther cryptocurrencies are split from the Bitcoin blockchain, such as LiteCoin and BitCoin Cash.

2. Ether Ethereum
Proposed by Vitalik Buterin in 2013, it is currently the cryptocurrency with the second highest market value. Vitalik wants to build a platform based on a decentralized blockchain to run Smart Contracts. This platform is called Ethereum. Ether is a media that pays fees when running programs on the Ethereum platform. It is very different from BitCoin's positioning of becoming a currency for daily use. Several other major differences include: the circulation of Ether is unlimited, and Ether uses PoS (Proof-of-Stake), while BitCoin uses PoW (Proof-of-Work).

3. LiteCoin Litecoin
In July 2011, it was forked from the BitCoin Blockchain by former Google employee Charlie Lee. There are only two differences from BitCoin:
1. BitCoin is generated every 10 minutes. The next block, LiteCoin only takes 2.5 minutes
2. BitCoin uses SHA256 as the Hash function, and LiteCoin uses Scrypt (a Memory hard function). The purpose is to enable ordinary people to participate in mining and profit using home computers, breaking the BitCoin is currently monopolized by ASIC/FPGA.

4. Monero Monero
A cryptocurrency created entirely for privacy, pushing the anonymity of Bitcoin to the extreme, even the transaction amount and destination address are not disclosed to the network. There is no upper limit in theory. In fact, after the 18.3 millionth Monero is mined, only 0.3 new Moneros are added every minute. In 2017, the WannaCry virus attacked Windows users on a large scale, locking all computer files and extorting users' BitCoin. Later, an investigation found that the hackers later exchanged the BitCoin for Monero, and thereafter the money could not be followed.

5. Tether (USDT)
Unlike all other cryptocurrencies, the value of USDT is linked to the US dollar. 1USDT should be exactly equal to 1USD, although in reality there is often a few% gap. Only Kraken exchange can convert USDT into USD. According to the Tether white paper, every USDT is backed by a USD, and this large amount of US dollar cash is deposited in a Hong Kong company, Tether Limited. Using USDT instead of USD hasSeveral benefits: save handling fees for remittances to major cryptocurrency exchanges; save time for depositing into exchanges, etc.

6. DogeCoin Dogecoin
A cryptocurrency originally created just for fun, it uses Scrypt like Litecoin, but there is no upper limit on the quantity. The main use of Dogecoin is charity fundraising. For example, during the 2014 Winter Olympics, a Jamaican bobsleigh team qualified for the Winter Olympics but had no funds to compete. The Dogecoin community represented the team. They raised US$50,000 to sponsor them to compete in Sochi, Russia.

❻ What are the characteristics of the blockchain?

The characteristics of the blockchain are:

1. It cannot be tampered

The most easily understood feature of blockchain is that it cannot be tampered with. Immutability is based on the unique ledger of "block + chain": blocks containing transactions are continuously added to the end of the chain in chronological order. To modify the data in a block, all blocks after it need to be regenerated.

2. Uniqueness required to express value

Whether it is an interchangeable token (ERC20), a non-interchangeable token (ERC721), or other proposals The token standards and Ethereum tokens all demonstrate an important feature of the blockchain: the uniqueness required to represent value. In the digital world, the most basic unit is a bit, and the fundamental characteristic of a bit is that it can be copied. But the value cannot be copied, the value must be unique.

3. Smart contracts

From Bitcoin to Ethereum, the biggest change in the blockchain is the "smart contract". The Bitcoin system is designed for a digital currency, and its UTXOs and scripts can also handle some complex transactions, but they have significant limitations. When Vitalik created the Ethereum blockchain, his core goals revolved around smart contracts: a Turing-complete scripting language, a virtual machine (EVM) to run smart contracts, and a series of subsequent developments. Standardized smart contracts for different types of tokens, etc.

4. Decentralized self-organization

The fourth major feature of the blockchain is decentralized self-organization. So far, the organization and operations of major blockchain projects have been closely tied to this characteristic. Many people’s ideal expectation for blockchain projects is that they become a community or ecosystem that operates autonomously.

5. Openness.

The foundation of blockchain technology is open source. In addition to the private information of the transaction parties being encrypted, the blockchain data is open to everyone. Anyone can query the blockchain data through the public interface. and develop related applications, so the entire system information is highly transparent.

❼ What is a smart contract?

A program that runs on the blockchain is usually called a smart contract. So we usually writeBlockchain programs are renamed to write smart contracts.
Although smart contracts can also be written on Bitcoin, the syntax supported by Bitcoin is only related to transactions, and what can be done is relatively limited.
So when it comes to writing smart contracts, it usually refers to the Ethereum blockchain that supports the execution of Turing-complete programs.

❽ What are side chains and main chains in blockchain

Main chain: that is, an officially launched, independent blockchain network. It can be said that the entity that stores data in the blockchain is generally considered to be the main chain network itself. For example, BTC mainnet, ETH mainnet and EOS mainnet are all main chains.

Sidechain: First of all, the essence of the sidechain protocol is a cross-blockchain solution. Simply put, this solution allows data information to be transferred between two blockchains. Sidechains were originally proposed to enable the transfer of Bitcoin and other digital assets between multiple blockchains.

In layman’s terms, side chains are like pathways that connect different blockchains to each other to achieve the expansion of the blockchain. The side chain is completely independent of the main chain, but the two ledgers can "interoperate" and achieve interaction.

Sidechain protocol - Sidechain protocol refers to (taking Bitcoin as an example): it allows Bitcoin to be safely transferred from the Bitcoin main chain to other blockchains, and from other blockchains A protocol for securely returning to the Bitcoin main chain. The same goes for exchanging Bitcoin for Ethereum or other blockchains. So, why do we need side chains, or what are the benefits of side chains?

The functions that the main chain lacks are provided by the side chain.

For example, the Bitcoin network does not have the function of smart contracts, but this function can be realized through side chains.

If the operation efficiency of the main chain is low, some functions of the main chain can be transferred to the side chain for implementation.

For example, the transfer speed of the main chain is very slow and there is no way to meet daily payment needs. We can develop the Lightning Network as a side chain to meet daily payment needs. Also due to low performance, Ethereum cannot support large-scale commercial-level DAPPs (decentralized applications), which can be achieved through side-chain development.

If you put aside the technical rigor, you can use another simpler way to understand side chains. All networks that provide support or services for the original main network can be called side chains. No need to Care about whether this side chain uses blockchain technology. For example:

Third-party payment network (Alipay/WeChat), you can think of the bank network as the main chain, and third-party payment is a side chain.

Cryptocurrency trading considers free networks such as Bitcoin and other virtual currencies as the main chain, and the exchange can be regarded as a side chain.

RSK and Loom are separately developed side chains for the Bitcoin and Ethereum main chains respectively.

The first typeIn the application, the main chain and side chain are centralized

In the second application, the main chain is decentralized and the side chain is centralized

The third application, the main chain is decentralized, and the side chain is also decentralized. With the deepening of blockchain technology, we can see that human value exchange activities will slowly evolve from the first application. Gradually transition to the third application.

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❾ Does Bitcoin support smart contracts?

Bitcoin does not support point-to-point transmission at present

❿ "Blockchain Technology Drives Financial Digital Currency and Smart Contracts" Technology" pdf download and online reading, please seek Baidu network disk cloud resources

"Blockchain Technology Drives Finance" (Arvind Narayanan) e-book network disk download for free online reading

Resource link:

Link: https://pan..com/s/1kjXFQI1EYFZ3Yh0hIETszw Extraction code: fk9u

Book title: Blockchain Technology Drives Finance

Author: Arvind Narayanan

Translator: Lin Hua

Douban score: 8.2

Publisher: CITIC Publishing House , CITIC Publishing Group

Publication year: 2016-8-25

Number of pages: 432

Content introduction:

From digital currency and smart contract technology, interpreting the application of blockchain technology in the financial field. "If you are looking for a technical explanation of how Bitcoin works, and you have some basic knowledge of computer science and programming, this book should be for you."

"Blockchain" "Technology Driven Finance" answers a series of questions about how Bitcoin operates using blockchain technology, and focuses on various technical functions and the network that will be formed in the future. How does Bitcoin work? What makes it different? Is your Bitcoin safe? How can Bitcoin users remain anonymous? How does blockchain help Bitcoin achieve identity-less consensus? What applications can we create on the Bitcoin platform? Can cryptocurrencies be regulated? What changes will creating a new digital currency bring? How will the future develop?

After reading this book, you will know all about Bitcoin and other digital currencies, have a basic understanding of blockchain technology, and be able to distinguish completely fictional stories.. You will have a basic idea of what kind of security software is needed, how to interact with the Bitcoin network, and you can also integrate blockchain concepts into your own projects. You will become the leader of the times!

About the author:

Arvind Narayanan is an associate professor and scientist in the Department of Computer Science at Princeton University.

Josh Bennu is a technician at the Electronic Frontier Foundation and a postdoctoral fellow at Stanford University.

Edward Felton, professor of computer science and public affairs at Princeton University, was appointed as President Obama’s technology advisor in 2015.

Andrew Miller, PhD in computer science from the University of Maryland.

Steven Goldfeder, PhD in computer science from Princeton University.

Translator's introduction:

Lin Hua, President of China Securitization Research Institute, Chairman of China Securitization Analysis Network, CEO of China Fund Administration Network, Independent Director of Industrial Bank .

Wang Yong, chief risk officer of Everbright Securities.

Shuai Chu, Chief Technology Officer of VeChain Technology (vechain), designer of QtumChain, China’s open source blockchain platform.

Cai Kailong is the founder of Dianshi Asset Management, chairman of the executive committee of Xiamen Tiqian Lundao Asset Management Company, and co-founder of the Internet Finance Thousand People Association.

Xu Yujie is the research director of United Credit Ratings Co., Ltd., chief researcher of China Asset Securitization Research Institute, and distinguished researcher of Southwestern University of Finance and Economics.

Li Yaoguang, director of structured finance of a joint venture securities company.

Gao Xiaojing, Investment Banking Department of Industrial Bank Head Office.

Hong Hao, Bond and Structural Finance Department of Zhongtai Securities.