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goupee.vn goupee.com Blockchain IBM Limited Edition by Manav Gupta fb.com/goupee.vn These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com Blockchain For Dummies®, IBM Limited Edition Published by John Wiley & Sons, Inc. 111 River St. Hoboken, NJ 07030-5774 www.wiley.com Copyright © 2017 by John Wiley & Sons, Inc. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without the prior written permission of the Publisher. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at http://www.wiley.com/go/permissions. Trademarks: Wiley, For Dummies, the Dummies Man logo, The Dummies Way, Dummies.com, Making Everything Easier, and related trade dress are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates in the United States and other countries, and may not be used without written permission. IBM and the IBM logo are registered trademarks of International Business Machines Corporation. All other trademarks are the property of their respective owners. John Wiley & Sons, Inc., is not associated with any product or vendor mentioned in this book. LIMIT OF LIABILITY/DISCLAIMER OF WARRANTY: THE PUBLISHER AND THE AUTHOR MAKE NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS WORK AND SPECIFICALLY DISCLAIM ALL WARRANTIES, INCLUDING WITHOUT LIMITATION WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE. NO WARRANTY MAY BE CREATED OR EXTENDED BY SALES OR PROMOTIONAL MATERIALS. THE ADVICE AND STRATEGIES CONTAINED HEREIN MAY NOT BE SUITABLE FOR EVERY SITUATION. THIS WORK IS SOLD WITH THE UNDERSTANDING THAT THE PUBLISHER IS NOT ENGAGED IN RENDERING LEGAL, ACCOUNTING, OR OTHER PROFESSIONAL SERVICES. IF PROFESSIONAL ASSISTANCE IS REQUIRED, THE SERVICES OF A COMPETENT PROFESSIONAL PERSON SHOULD BE SOUGHT. NEITHER THE PUBLISHER NOR THE AUTHOR SHALL BE LIABLE FOR DAMAGES ARISING HEREFROM. THE FACT THAT AN ORGANIZATION OR WEBSITE IS REFERRED TO IN THIS WORK AS A CITATION AND/OR A POTENTIAL SOURCE OF FURTHER INFORMATION DOES NOT MEAN THAT THE AUTHOR OR THE PUBLISHER ENDORSES THE INFORMATION THE ORGANIZATION OR WEBSITE MAY PROVIDE OR RECOMMENDATIONS IT MAY MAKE. FURTHER, READERS SHOULD BE AWARE THAT INTERNET WEBSITES LISTED IN THIS WORK MAY HAVE CHANGED OR DISAPPEARED BETWEEN WHEN THIS WORK WAS WRITTEN AND WHEN IT IS READ. For general information on our other products and services, or how to create a custom For Dummies book for your business or organization, please contact our Business Development Department in the U.S. at 877-409-4177, contact info@dummies.biz, or visit www.wiley.com/go/custompub. For information about licensing the For Dummies brand for products or services, contact BrandedRights& Licenses@Wiley.com. ISBN: 978-1-119-37123-6 (pbk); ISBN: 978-1-119-37139-7 (ebk) Manufactured in the United States of America 10 9 8 7 6 5 4 3 2 1 Publisher’s Acknowledgments Some of the people who helped bring this book to market include the following: Project Editor: Carrie A. Burchfield Business Development Editorial Manager: Rev Mengle Representative: Sue Blessing Acquisitions Editor: Steve Hayes Production Editor: Vasanth Koilraj fb.com/goupee.vn These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com Table of Contents INTRODUCTION............................................................................................... 1 About This Book ................................................................................... 1 Foolish Assumptions............................................................................ 2 Icons Used in This Book....................................................................... 2 CHAPTER 1: Grasping Blockchain Fundamentals............................ 3 Tracing Blockchain’s Origin ................................................................. 3 The shortcomings of current transaction systems..................... 4 The emergence of bitcoin .............................................................. 5 The birth of blockchain .................................................................. 6 Revolutionizing the Traditional Business Network .......................... 6 Exploring a blockchain application ............................................... 7 Recognizing the key business benefits ......................................... 9 Building trust with blockchain..................................................... 10 CHAPTER 2: Taking a Look at How Blockchain Works............... 13 Why It’s Called “Blockchain” .............................................................. 13 What Makes a Blockchain Suitable for Business? .......................... 14 Shared ledger ................................................................................ 15 Permissions ................................................................................... 15 Consensus...................................................................................... 16 Smart contracts............................................................................. 17 Identifying Participants and Their Roles.......................................... 18 CHAPTER 3: Propelling Business with Blockchains...................... 19 Recognizing Types of Market Friction .............................................. 20 Information frictions..................................................................... 20 Interaction frictions ...................................................................... 20 Innovation frictions....................................................................... 21 MovingClosertoFriction-FreeBusinessNetworks ....................... 21 Reducing information friction ..................................................... 22 Easing interaction friction ............................................................ 22 Easing innovation friction ............................................................ 23 Transforming Ecosystems through Increased Visibility................. 24 fb.com/goupee.vn Table of Contents iii These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com CHAPTER 4: Blockchain in Action: Use Cases.................................... 25 Financial Services ............................................................................... 25 Commercial financing................................................................... 25 Trade finance................................................................................. 26 Cross-border transactions ........................................................... 26 Insurance............................................................................................. 27 Government ........................................................................................ 27 Supply Chain Management............................................................... 28 Healthcare ........................................................................................... 29 Electronic medical records .......................................................... 29 Healthcare payments pre-authorization.................................... 29 The Internet of Things (IoT)............................................................... 30 CHAPTER 5: Hyperledger, a Linux Foundation Project ............ 31 Hyperledger Vision............................................................................. 32 Hyperledger Fabric............................................................................. 33 HowCanIBMHelpDevelopersInnovateWithBlockchain? .......... 34 Offeringaneasilyaccessiblecloudand development platform ................................................................. 34 Individualized attention and industry expertise ....................... 35 CHAPTER 6: Ten Steps to Your First Blockchain application...................................................................................... 37 Deciding Whether Blockchain Has a Place in Your Industry ......... 37 Identifying Speed Bumps in Business Processes ........................... 38 Determining How Blockchain Can Help .......................................... 38 Choosing an Appropriate Use Case ................................................. 39 Determining the Goal of Your Blockchain Network ....................... 39 Identifying Dependencies.................................................................. 39 Choosing a Blockchain Provider and Platform ............................... 40 Developing and Deploying Chaincode............................................. 40 TestingandFine-TuningYourApplicationandNetwork ............... 41 Joining the Hyperledger Rocket Chat Channel................................ 41 iv Blockchain For Dummies,fb.com/goupee.vnIBM Limited Edition These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com Introduction Wyour guide to all things blockchain for business. It haselcome to Blockchain For Dummies, IBM Limited Edition, been said that blockchain will do for transactions what the Internet did for information. What that means is that it allows increased trust and efficiency in the exchange of almost anything. Blockchain can profoundly change how the world works. If you’ve ever bought a house, you probably had to sign a huge stack of papers from a variety of different stakeholders to make that transaction happen. If you’ve ever registered a vehicle, you may understand how painful that process can be. I won’t even get started on how challenging it can be to track your medical records. Blockchain, most simply defined as a shared, immutable ledger, has the potential to be the technology that redefines those pro - cesses and many others. To be clear, when I talk about blockchain, I’m not talking about bitcoin. I’m talking about the underlying digital foundation that supports applications such as bitcoin. But the reaches of blockchain extend far beyond bitcoin. About This Book Blockchain For Dummies, IBM Limited Edition, equips you with an understanding of what blockchain is, how it works, and how it can enhance your business and the industry in which it operates. You learn the fundamentals of blockchain and how this technology will revolutionize transactions and business networks. You also discover the important difference between blockchain and block- chain for business and what makes blockchain an ideal solution for streamlining business networks. You will also discover Hyperledger, a Linux Foundation project, designed to help advance technology and thought leadership of cross-industry blockchain technologies. You learn about Hyperledger Fabric, an open source framework, and the- instru mental role it plays in developing a blockchain for business. Finally, you find out everything you need to spin up a blockchain network today. fb.com/goupee.vn Introduction 1 These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com Foolish Assumptions I wrote this book based on certain assumptions about you, the reader, to tailor the content of this book and its presentation to the proper audience. First, I assume that you’re a developer who’s relatively new to blockchain, although the less technical parts of this book may also be of interest to business owners and decision makers. Regardless of your role, I assume you’re interested in finding out more about blockchain and its tremendous potential. I also assume you want to know more about the steps you need to take to start deploying blockchain-based business networks. Icons Used in This Book Every For Dummies book has small images, called icons, sprinkled throughout the margins. I use the following icons in this book: This icon guides you to faster, easier ways to perform a task or better ways to put blockchain to use in your business. This icon highlights concepts worth remembering and other important topics. If you see this icon, proceed with caution. Here you find advice on how to avoid the most common pitfalls. Seek out this icon if you want to find out more about blockchain and related topics on the web. 2 Blockchain For Dummies,fb.com/goupee.vnIBM Limited Edition These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn IN THIS CHAPTER goupee.com » Exploring the roots of the shared ledger system » Appreciating blockchain’s business potential Chapter1 Grasping Blockchain Fundamentals Bprocess of recording transactions and tracking assets in alockchain is a shared, distributed ledger that facilitates the business network. An asset can be tangible — a house, a car, cash, land — or intangible like intellectual property, such as patents, copyrights, or branding. Virtually anything of value can be tracked and traded on a blockchain network, reducing risk and cutting costs for all involved. That’s the elevator speech for blockchain. In the rest of this chapter, I provide additional details to help you more fully appreciate this technology and its potential for streamlining business operations. Tracing Blockchain’s Origin You can gain a deeper understanding of blockchain by exploring the context in which it was developed — the need for an efficient, cost-effective, reliable, and secure system for conducting and recording financial transactions. In this section, I provide that context and describe the characteristics of blockchain that make it such a suitable solution. CHAPTER 1fb.com/goupee.vnGrasping Blockchain Fundamentals 3 These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com The shortcomings of current transaction systems Throughout history, instruments of trust, such as minted coins, paper money, letters of credit, and banking systems, have emerged to facilitate the exchange of value and protect buyers and sellers. Important innovations, including telephone lines, credit card systems, the Internet, and mobile technologies have improved the convenience, speed, and efficiency of transactions while shrinking and sometimes virtually eliminating the distance between buyers and sellers. Still, many business transactions remain inefficient, expensive, and vulnerable, suffering from the following limitations: » Cash is useful only in local transactions and in relatively small amounts. » The time between transaction and settlement can be long. » Duplication of effort and the need for third-party validation and/or the presence of intermediaries add to the inefficiencies. » Fraud, cyberattacks, and even simple mistakes add to the cost and complexity of doing business, and they expose all participants in the network to risk if a central system, such as a bank, is compromised. » Credit card organizations have essentially created walled gardens with a high price of entry. Merchants must pay the high costs of onboarding, which often involves considerable paperwork and a time-consuming vetting process. » Half of the people in the world don’t have access to a bank account and have had to develop parallel payment systems to conduct transactions. Transaction volumes worldwide are growing exponentially and will surely magnify the complexities, vulnerabilities, ineffi- ciencies, and costs of current transaction systems. The growth of ecommerce, online banking, and in-app purchases, and the increasing mobility of people around the world have fueled the growth of transaction volumes. And transaction volumes will explode with the rise of Internet of Things (IoT) — autonomous objects, such as refrigerators that buy groceries when supplies are 4 Blockchain For Dummies,fb.com/goupee.vnIBM Limited Edition These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com running low and cars that deliver themselves to your door, stop- ping for fuel along the way. To address these challenges and others, the world needs payment networks that are fast and that provide a mechanism that establishes trust, requires no specialized equipment, has no chargebacks or monthly fees, and provides a collective bookkeeping solution for ensuring transparency and trust. The emergence of bitcoin One solution that has been developed to address the complexities, vulnerabilities, inefficiencies, and costs of current transaction systems is bitcoin — a digital currency that was launched in 2009 by a mysterious person (or persons) known only by the pseudonym Satoshi Nakamoto. Unlike traditional currencies, which are issued by central banks, bitcoin has no central monetary authority. No one controls it. Bitcoins aren’t printed like dollars or euros; they’re “mined” by people and increasingly by businesses, running computers all around the world, using software that solves mathematical puz- zles. Rather than rely on a central monetary authority to monitor, verify, and approve transactions and manage the money supply, bitcoin is enabled by a peer-to-peer computer network made up of its users’ machines, akin to the networks that underpin BitTor- rent and Skype. Bitcoin has several advantages over other current transaction systems, including the following: » Cost-effective: Bitcoin eliminates the need for intermediaries. » Efficient: Transaction information is recorded once and is available to all parties through the distributed network. » Safe and secure: The underlying ledger is tamper-evident. A transaction can’t be changed; it can only be reversed with another transaction, in which case both transactions are visible. CHAPTER 1fb.com/goupee.vnGrasping Blockchain Fundamentals 5 These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com The birth of blockchain Bitcoin is actually built on the foundation of blockchain, which serves as bitcoin’s shared ledger. Think of blockchain as an oper- ating system, such as Microsoft Windows or MacOS, and bitcoin as only one of the many applications that can be run on that oper- ating system. Blockchain provides the means for recording bitcoin transactions — the shared ledger — but this shared ledger can be used to record any transaction and track the movement of any asset whether tangible, intangible, or digital. For example, block- chain enables securities to be settled in minutes instead of days. It can also be used to help companies manage the flow of goods and related payments, or enable manufacturers to share production logs with original equipment manufacturers (OEMs) and regula- tors to reduce product recalls. The takeaway lesson: Bitcoin and blockchain are not the same. Blockchain provides the means to record and store bitcoin trans- actions, but blockchain has many uses beyond bitcoin. Bitcoin is only the first use case for blockchain. Revolutionizing the Traditional Business Network With traditional methods for recording transactions and track- ing assets, participants on a network keep their own ledgers and other records, as shown in the picture on the left in Figure 1-1. This traditional method can be expensive, partially because it involves intermediaries that charge fees for their services. It’s clearly inefficient due to delays in executing agreements and the duplication of effort required to maintain numerous ledgers. It’s also vulnerable because if a central system (for example, a bank) is compromised, due to fraud, cyberattack, or a simple mistake, the entire business network is affected. The picture on the right in Figure 1-1 represents business networks that use blockchain. The blockchain architecture gives participants the ability to share a ledger that is updated, through peer-to-peer replication, every time a transaction occurs.Peer- to-peer replication means that each participant (node) in the network acts as both a publisher and a subscriber. Each node can receive or send transactions to other nodes, and the data is synchronized across the network as it is transferred. 6 Blockchain For Dummies,fb.com/goupee.vnIBM Limited Edition These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com FIGURE 1-1: Business networks before and after blockchain. The blockchain network is economical and efficient, because it elim- inates duplication of effort and reduces the need for intermediaries. It’s also less vulnerable because it uses consensus models to validate information. Transactions are secure, authenticated, and verifiable. The participants in both transaction systems are the same. What has changed is that the transaction record is now shared and available to all parties. A blockchain network has the following key characteristics: » Consensus: For a transaction to be valid, all participants must agree on its validity. (See Chapter 2 for more about consensus mechanisms.) » Provenance: Participants know where the asset came from and how its ownership has changed over time. » Immutability: No participant can tamper with a transaction after it’s been recorded to the ledger. If a transaction is in error, a new transaction must be used to reverse the error, and both transactions are then visible. » Finality: A single, shared ledger provides one place to go to determine the ownership of an asset or the completion of a transaction. Exploring a blockchain application Car companies make leasing a vehicle look easy, but in reality, it can be quite complicated. A significant challenge faced by today’s car leasing networks is that even though the physical supply chain is usually integrated, the supporting systems are often frag- mented. Each party within the network maintains its own ledger, which can take days or weeks to synchronize (see Figure 1-2). CHAPTER 1fb.com/goupee.vnGrasping Blockchain Fundamentals 7 These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com FIGURE 1-2: Tracking vehicle ownership without blockchain. By using a shared ledger on a blockchain network, every partici- pant can access, monitor, and analyze the state of the vehicle irrespective of where it is within its life cycle (see Figure 1-3). FIGURE 1-3: Tracking vehicle ownership with blockchain. With blockchain, network participants can interact as follows: 1. The government regulator creates and populates the registration for the new vehicle on the blockchain and transfers the ownership of the vehicle to the manufacturer. 8 Blockchain For Dummies,fb.com/goupee.vnIBM Limited Edition These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com 2. The manufacturer adds the make, model, and vehicle identification number to the vehicle template within the parameters allowed by the smart contract (a digital agreement or set of rules that govern a transaction — see Chapter 2 for details). 3. The dealer can see the new stock availability, and ownership of the vehicle can be transferred from the manufacturer to the dealership after a smart contract is executed to validate the sale. 4. The leasing company can see the dealer’s inventory. Ownership of the vehicle can be transferred from the dealer to the leasing company after a smart contract is executed to validate the transfer. 5. The lessee can see the cars available for lease and complete any form required to execute the lease agreement. 6. The leasing process continues between various lessees and the leasing company until the leasing company is ready to retire the vehicle. At this point, ownership of the asset is transferred to the scrap merchant, who, according to another smart contract, has permission to dispose of the vehicle. Recognizing the key business benefits For business, blockchain has the following specific benefits: » Time savings: Transaction times for complex, multi-party interactions are slashed from days to minutes. Transaction settlement is faster, because it doesn’t require verification by a central authority. » Cost savings: A blockchain network reduces expenses in several ways: • Less oversight is needed because the network is self- policed by network participants, all of whom are known on the network. • Intermediaries are reduced because participants can exchange items of value directly. • Duplication of effort is eliminated because all participants have access to the shared ledger. CHAPTER 1fb.com/goupee.vnGrasping Blockchain Fundamentals 9 These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com » Tighter security: Blockchain’s security features protect against tampering, fraud, and cybercrime. If a network is permissioned, it enables the creation of a members-only network with proof that members are who they say they are and that goods or assets traded are exactly as represented. Not all blockchains are built for business. Some are permissioned while others aren’t. A permissioned network is critical for a block- chain for business, especially within a regulated industry. It offers » Enhanced privacy: Through the use of IDs and permissions, users can specify which transaction details they want other participants to be permitted to view. Permissions can be expanded for special users, such as auditors, who may need access to more transaction detail. » Improved auditability: Having a shared ledger that serves as a single source of truth improves the ability to monitor and audit transactions. » Increased operational efficiency: Pure digitization of assets streamlines transfer of ownership, so transactions can be conducted at a speed more in line with the pace of doing business. Chapter 2 goes into more detail on what makes a blockchain net- work ideal for business. Building trust with blockchain Blockchain enhances trust across a business network. It’s not that you can’t trust those who you conduct business with; it’s that you don’t need to when operating on a blockchain network. Blockchain is particularly valuable at increasing the level of trust among network participants. Because every transaction builds on every other transaction, any corruption is readily apparent, and everyone is made aware of it. This self-policing can mitigate the need to depend on the current level of legal or government safe- guards and sanctions to monitor and control the flow of business transactions. The community of participants does that. Where third-party oversight is required, blockchain reduces the burden on the regulatory system by making it easier for auditors and regulators to review relevant transaction details and verify compliance. 10 Blockchain For Dummies,fb.com/goupee.vnIBM Limited Edition These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com Blockchain builds trust through the following five attributes: » Distributed and sustainable: The ledger is shared, updated with every transaction, and selectively replicated among participants in near real time. Because it’s not owned or controlled by any single organization, the blockchain platform’s continued existence isn’t dependent on any individual entity. » Secure, private, and indelible: Permissions and cryptogra- phy prevent unauthorized access to the network and ensure that participants are who they claim to be. Privacy is main- tained through cryptographic techniques and/or data partitioning techniques to give participants selective visibility into the ledger; both transactions and the identity of transact- ing parties can be masked. After conditions are agreed to, participants can’t tamper with a record of the transaction; errors can be reversed only with new transactions. » Transparent and auditable: Because participants in a transaction have access to the same records, they can validate transactions and verify identities or ownership without the need for third-party intermediaries. Transactions are time-stamped and can be verified in near real time. » Consensus-based and transactional: All relevant network participants must agree that a transaction is valid. This is achieved through the use of consensus algorithms. Each blockchain network can establish the conditions under which a transaction or asset exchange can occur. » Orchestrated and flexible: Because business rules and smart contracts (that execute based on one or more conditions) can be built into the platform, blockchain business networks can evolve as they mature to support end-to-end business processes and a wide range of activities. CHAPTER 1fb.com/goupee.vnGrasping Blockchain Fundamentals 11 These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn IN THIS CHAPTER goupee.com » Breaking down the “blockchain” concept » Understanding what makes a blockchain network suitable for business » Checking out the network participants and the roles they play Chapter2 Taking a Look at How Blockchain Works While Chapter 1 gives you a general understanding ofwhat blockchain is and an appreciation of what it can do, you may be wondering how it works. In this chapter, I tackle that topic by taking you behind the scenes of a blockchain network without getting overly technical. Here, you get a glimpse of how blockchain stores transactions in a way that prevents recorded transactions from being changed. You discover the four concepts that form the foundation of a block- chain for business, and you meet the network participants and find out about the various roles they play. Why It’s Called “Blockchain” Blockchain owes its name to the way it stores transaction data — in blocks that are linked together to form a chain (see Figure 2-1). As the number of transactions grows, so does the blockchain. Blocks record and confirm the time and sequence of transactions, which are then logged into the blockchain, within a discrete net- work governed by rules agreed on by the network participants. CHAPTER 2fb.com/goupee.vnTaking a Look at How Blockchain Works 13 These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com FIGURE 2-1: Blockchain stores transaction records in a series of connected blocks. Each block contains a hash (a digital fingerprint or unique identi- fier), timestamped batches of recent valid transactions, and the hash of the previous block. The previous block hash links the blocks together and prevents any block from being altered or a block being inserted between two existing blocks. In this way, each subsequent block strengthens the verification of the previ- ous block and hence the entire blockchain. The method renders the blockchain tamper-evident, lending to the key attribute of immutability. To be clear, while the blockchain contains transaction data, it’s not a replacement for databases, messaging technology, transac- tion processing, or business processes. The blockchain contains verified proof of transactions. However, while blockchain essen- tially serves as a database for recording transactions, its benefits extend far beyond those of a traditional database. What Makes a Blockchain Suitable for Business? Instead of having a blockchain that relies on the exchange of cryptocurrencies with anonymous users on a public network (as is the case with bitcoin), a blockchain for business is a private, per- missioned network with known identities and without the need for cryptocurrencies. To further understand how a blockchain for business works, and to appreciate its potential for revolutionizing business networks, you need to understand the four key concepts of blockchain for business, shown in Figure 2-2. 14 Blockchain For Dummies,fb.com/goupee.vnIBM Limited Edition These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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goupee.vn goupee.com FIGURE 2-2: The key concepts of blockchain for business. These four concepts are explained in this section. Shared ledger Ledgers are nothing new; they’ve been used in double-entry bookkeeping since the 13th century. What is new is the concept of a shared, distributed ledger — an immutable record of all trans- actions on the network, a record that all network participants can access. With a shared ledger, transactions are recorded only once, eliminating the duplication of effort that’s typical of tra- ditional business networks. The shared ledger has the following characteristics: » Records all transactions across the business network; the shared ledger is the system of record, the single source of truth. » Is shared among all participants in the network; through replication, each participant has a duplicate copy of the ledger. » Is permissioned, so participants see only those transactions they’re authorized to view. Participants have identities that link them to transactions, but they can choose the transaction information that other participants are authorized to view. Permissions Blockchains can be permissioned or permissionless. With a permissioned blockchain, each participant has a unique identity, which enables the use of policies to constrain network participation and access to transaction details. With the ability to constrain network participation, organizations can more easily comply with data protection regulations, such as those stipulated in the Health Insurance Portability and Accountability Act (HIPAA). Permissioned blockchains are also more effective at controlling the consistency of the data that gets appended to the blockchain. CHAPTER 2 fb.com/goupee.vnTaking a Look at How Blockchain Works 15 These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.
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