Head First Blockchina 3

Hyperledger Fabric for Mortals

HyperLedger, from Arvind Krishna, Director of IBM research lab, meant to cross borders. e.g. for credit ledger, the importer and exporter in China need to make preparations few months beforehand, this is similiar to Marco Polo went to China 300 years ago.

Another usage in stock market is stock loan, by using blockchain, we are going to know whose the stock came from. And the borrowers need to know who can borrow, and I need to prepare collaterials, need to check whether it comply with the processes, when I pay it back, etc. there are lots of things. right now they are handled by people manually, so going forward, if I have some stocks and I want to borrow it to earn some money, those can be programmed in blockchain. they’ll be processed by machines automatically. this will help to show there are no inside tradings, etc.

but initially as blockchian are annoymous, we are not sure whthere there are any money laundering, regulators may have concerns. So we need permisisoned blockchains. we need to one identity put aside of the transactions, so if reuiqred, can be recorded and checked, e.g. whether this is dealing with corrupted governments, etc. in addtion, it’s not requried that only one player or government to provide identity, there are many entities can provide identity service, but off couse need to follow some standards agreed.

JPMorgan Chase & Co has announced its second entrant into the blockchain fray, this time utilizing the smart contract enabled ethereum blockchain in creating a system called Quorum.

前面第一章讲过了基本概念，可能有此抽象。接下来我们来看一些目前已经存在的真实项目和案例，好有一些形象的理解，以便为后面深入一些概念准备。

1. JPMorgan 的 Juno
2. Ripple 全球化交割网络
3. R3 DEV
4. 以态坊
5. 万象Lab

All of the advantages derived from basic blockchain technology can be boiled down to only two benefits; corruption resistance and redundancy.

All of the advantages derived from basic blockchain technology can be boiled down to only two benefits; corruption resistance and redundancy.

The crux of the issue comes down to whether or not private blockchains can ever be made secure enough to use for large amounts of value. No hacker is going to bother to attack your blockchain if it’s only being used for bingo night at a retirement home. However, the moment the world finds out that your blockchain has millions of dollars worth of payments flowing across it, you’ve basically just launched the latest hackathon, complete with a multi-million dollar, winner-take-all grand prize.

For instance, a public blockchain is a transparency engine. In Vitalik Buterin’s blog post ‘On Public and Private Blockchains’ ‘On Public and Private Blockchains’ written last August, he pointed out that public blockchains “protect the users of an application from the developers, establishing that there are certain things that even the developers of an application have no authority to do.” A good example of this is a user of a social network or some other membership site where the owner changing

http://www.youtube.com/watch?v=810aKcfM__Q

The main takeaway is that permissioned blockchains create an environment where malware has an advantage,so security problems are constant and sometimes completely overcome your network.

First of all, the transaction speed of a privately-run blockchain can be faster than any other blockchain solution, approaching even the speeds of a normal database that isn’t a blockchain. This is because there are few nodes all with high trust levels. No need for every node to verify a transaction, in fact, they’re all mostly trusted so there is no need to do all of the meticulous work.

Complete agreement between nodes isn’t required, so fewer nodes need to do the work for any one transaction. Lastly, and perhaps most importantly in the current environment of banks embracing private blockchains so readily, choosing a private blockchain can help protect their underlying product from disruption.

Lastly, there is the desktop route, deploying a private blockchain on your desktop computer, even in a windows environment, with Multichain. It allows rapid design, deployment and operation of private blockchains to your custom specification.

http://r3members.com/

like unique keys and check constraints cannot protect a database against malicious modifications. The bottom line is this: We need a whole bunch of new stuff for shared write databases to work, and it just so happens that blockchains provide them.

Some key elements include regular peer-to-peer techniques, grouping transactions into blocks, one-way cryptographic hash functions, a multi-party consensus algorithm, Some key elements include regular peer-to-peer techniques, grouping transactions into blocks, one-way cryptographic hash functions, a multi-party consensus algorithm,

These types of rules can be expressed as bitcoin-style transaction constraints or Ethereum-style enforced stored procedures (“smart contracts”), each of which has advantages and disadvantages.

One key difference is that private blockchains don’t need proof of work mining,since blocks are created by a closed set of identified participants.

First, fear of the loss of raw power they would sustain if they went with public blockchains. Second, the fear of being supplanted by a new rising, bitcoin-centric financial industry. In fact, they would prefer that blockchain technology had never been invented.

区块链都足以产生影响和改变金融业的力量。这是由于区块链具有以下特点：（1）去中心化：区块链技术不依赖额外的第三方管理机构或硬件设施，没有中心管制，除了自成一体的区块链本身，通过分布式核算和存储，各个节点实现了信息自我验证、传递和管理。（2）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。（3）独立性：基于协商一致的规范和协议（类似比特币采用的哈希算法等各种数学算法），整个区块链系统不依赖其他第三方，所有节点能够在系统内自动安全地验证、交换数据，不需要任何人为的干预。（4）安全性：只要不能掌控全部数据节点的51%，就无法肆意操控修改网络数据，这是区块链本身变得相对安全，避免了主观人为的数据变更。（5）匿名 区块链都足以产生影响和改变金融业的力量。这是由于区块链具有以下特点：（1）去中心化：区块链技术不依赖额外的第三方管理机构或硬件设施，没有中心管制，除了自成一体的区块链本身，通过分布式核算和存储，各个节点实现了信息自我验证、传递和管理。（2）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。（3）独立性：基于协商一致的规范和协议（类似比特币采用的哈希算法等各种数学算法），整个区块链系统不依赖其他第三方，所有节点能够在系统内自动安全地验证、交换数据，不需要任何人为的干预。（4）安全性：只要不能掌控全部数据节点的51%，就无法肆意操控修改网络数据，这是区块链本身变得相对安全，避免了主观人为的数据变更。（5）匿名. 正是这些优势特点，决定区块链技术能够提高系统的追责性，降低系统的信任风险，对优化金融机构业务流程、提高金融机构的竞争力具有相当重要的意义；通过使用区块链技术，金融信息和金融价值能够得到更加严格的保护，能够实现更加高效、更低成本的流动，从而实现价值和信息的共享。

区块链技术可通过程序化记录、存储、传递、核实、分析信息数据，从而形成信用，可以大量省去人力成本、中介成本，信用记录完整、难以造假，同时摧毁某些节点对系统没有影响。目前最大区块链比特币链存在费用增加、容量限制、确认时间变长、能耗走高的缺点。但例如Ripple、以太坊等另类区块链，以及公共、私有、联盟链等多种形式的涌现将区块链在金融领域造成颠覆式创新变成可能。

https://ripple.com/

只要诚实的节点所控制的计算能力的总和，大于有合作关系的(cooperating)攻击者的计算能力的总和，该系统就是安全的

Retail Giant Overstock to Issue its Own Stock on Blockchain Platform

Referece

• Hyperledger Whitepaper
• About blockchain
• IBM Blockchain for developers
• Getting started with IBM Blockchain
• IBM Blockchain 101: Quick-start guide for developers

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