An Introduction toHyperledger
Purpose of This Paper
This paper provides a high-level overview of Hyperledger: Why it was created,
how it is governed, and what it hopes to achieve. The core of this paper presents
five compelling uses for enterprise blockchain in different industries. It also
describes the open source frameworks and tools that Hyperledger is developing
to help enterprises around the world deliver on the promise of blockchain for
more secure, more reliable, and more streamlined interactions.
This is not intended as a deep technical white paper, but an introduction toHyperledger for a general business reader.

Intended Audience

ABOUT HYPERLEDGER
Hyperledger is an open source
collaborative effort created toadvance cross-industry blockchain
technologies. It is a global
collaboration including leaders
in banking, finance, Internet ofThings, manufacturing, supply
chains, and technology. The
Linux Foundation hosts
Hyperledger under the foundation.
To learn more, visit: hyperledger.
org. Hyperledger does notpromote a single blockchain
codebase or a single blockchain
project. Rather, it enables aworldwide developer community
to work together and shareideas, infrastructure, and code.

We expect this paper will be read by business people from different backgrounds,
including entrepreneurs, executives, IT managers, and software developers.
Since the blockchain is so new, we expect different readers will be more or lessfamiliar with certain blockchain terms and concepts. And since Hyperledger is aworldwide project, we expect this paper will be read by people around the world,many of whom do not have English as their first language.
Therefore, we tried to make this paper as clear and readable as possible. The
Further Resources section at the end points to more introductory and moreadvanced materials you may want to explore.

1 Introduction
2 Why Open Source for Blockchain?
3 The Greenhouse for Enterprise Blockchain
4 Hyperledger Design Philosophy
5 Some Compelling Use Cases
5.1 Banking: Applying for a Loan
5.2 Financial Services: Post-Trade Processing
5.3 Healthcare: Credentialing Physicians
5.4 IT: Managing Portable Identities
5.5 Supply Chain Management: Tracking Fish from Ocean to Table

6 Current Projects: Frameworks
6.1 Hyperledger Burrow
6.2 Hyperledger Fabric6.3 Hyperledger Indy
6.4 Hyperledger Iroha
6.5 Hyperledger Sawtooth

7 Current Projects: Tools
7.1 Hyperledger Caliper
7.2 Hyperledger Cello
7.3 Hyperledger Composer
7.4 Hyperledger Explorer
7.5 Hyperledger Quilt

8 Long-Term Vision
9 Conclusions
Notes

3
6
8
10
12
12
13
15
17
20
22
22
23
23
24
25
27
27
28
28
28
29
30
31
33

V1.1 published August 2018.
This work is licensed under a Creative Commons Attribution 4.0 International License
creativecommons.org/licenses/by/4.0
Acknowledgements
The Hyperledger White Paper Working Group would like to thank all the following people for contributing to this paper:
Tamas Blummer, Sean Bohan, Mic Bowman, Christian Cachin, Nick Gaski, Nathan George, Gordon Graham, Daniel
Hardman, Ram Jagadeesan, Travin Keith, Renat Khasanshyn, Murali Krishna, Tracy Kuhrt, Arnaud Le Hors, Jonathan
Levi, Stanislav Liberman, Esther Mendez, Dan Middleton, Hart Montgomery, Dan O’Prey, Drummond Reed, Stefan
Teis, Dave Voell, Greg Wallace, Baohua Yang.
We would also like to thank the Hyperledger Technical Steering and Marketing Committees for their valuable
feedback throughout the writing of this paper.

1 Introduction
This section explains the basic concepts of blockchain as a new type of shared database or
distributed ledger.
Databases are everywhere
Everyone has heard of “databases.” We use them every day. For example, the contacts list ona phone is a simple database—an electronic version of a paper address book.
More elaborate databases include lists of customers, employees, patients, or voters, and theirproperties and relationships. Even more complex databases might contain lists of instructions
or programs that can interact with one another.
In fact, you can think of a database as any organized set of information where you can findand possibly update items.
Ever since the computer revolution began in the 1950s, databases have played an importantpart in business and society. Databases began as simple applications with all the data arranged inflat files, like a list of contacts. Then they evolved to use hierarchies—more like org charts.
As companies called for more speed and power, databases became relational with all theinformation arranged as rows and columns in tables. You can query a relational database topull out specific information, such as all your contacts called “Smith” who live in Oregon. You
can’t do that with a paper address book.
Many databases today are shared
By now, the world is so connected that different people often need to access the same data.
To meet this need, distributed databases have emerged, where certain chunks of data canbe accessed by more than one person at once.
For example, to make it simpler to set up or reschedule meetings, all the members of a workgroup
can share their meetings on an online calendar. You can’t do that with a paper calendar.
Of course, more elaborate shared databases are used in business. Consider a company’s listof stock on hand, organized by SKU, and shared by the order desk at head office and by asales rep with a laptop in the field.
Both the home office and the sales rep can query the database to see what’s in stock, takeorders, and allocate stock-on-hand to customers.
But shared databases raise questions
Once you start sharing a database with others, many questions arise:•

Who do you trust to share your data?

•

How can you tell that someone is who they say they are online?

•

What are they allowed to do to the database?

•

What happens if both head office and the sales rep want to sell the same items?

•

Who settles any conflicts or disputes?

Clearly, there are many practical issues with sharing a database. Over the years, people have
tried many different solutions. One exciting new way to share databases that can help solvethese problems is through blockchain technology.

3

Blockchain is the technology behind Bitcoin
The media is full of stories on Bitcoin and other cryptocurrencies. But most businesses
don’t care too much about cryptocurrencies. Most businesses are happy buying andselling with dollars, euros, pounds, yen, or any other accepted currency —perhaps even acryptocurrency—as long as it works for them.
What’s far more significant for enterprises is the technology behind cryptocurrencies, calledblockchain.
“It’s not Bitcoin, the still speculative asset, that should interest you,” write Don and Alan
Tapscott in their book Blockchain Revolution.1 Instead, they point to “the power and potentialof the underlying technological platform” as what will interest most business people.
Blockchain is a new form of shared database
A blockchain is a distributed database with no central authority and no point of trust. When
you want to share a database, but you don’t have a lot of trust in the other people who mightuse it, a blockchain can be very helpful.
In this context, “trust” could mean many things. Trust could mean trusting others to perform
actions on the database properly. Trust could mean not trying to pry into each other’s private
information. Or trust could mean not degrading someone else’s performance to gain acompetitive advantage.
Discussing trust brings up the two main kinds of blockchain.
Most cryptocurrencies use permissionless blockchains where anyone can join and have fullrights to use it. For example, anyone can buy Bitcoin or Ether because those use wide-open,
permissionless blockchains.
On the other hand, business blockchains tend to be permissioned. This means a person
needs to meet certain requirements to perform certain actions on the blockchain. Somepermissioned blockchains restrict access to pre-verified users who have already proven they
are who they say they are. Others allow anyone to join, but only let trusted identities verify
transactions on the blockchain.
Remember our example of the database shared between head office and the field reps of acompany. If a blockchain was used to manage that database, it would definitely be permissioned:
Everyone accessing the blockchain would have to be an employee of the company or
perhaps a trusted trading partner.
Blockchain permissions and consensus
In the database shared between head office and field reps, this question came up: What happens
if two different reps want to sell the same items, but there aren’t enough on hand to fill both orders?
If that database were managed with a permissioned blockchain, this problem could be solved
through a process called consensus.
Blockchains use consensus systems to make sure the information in the database is always
correct. For example, a consensus system would use pre-established rules to determine
which field rep gets the limited items in stock.
Consensus systems take many different forms with different names.
For instance, Bitcoin uses a proof-of-work consensus, where the participants’ computerssolve difficult math problems. Other types of consensus are called proof of elapsed timeand proof of stake. Many permissioned blockchains use something called Byzantine FaultTolerant consensus algorithms.
No matter how they’re built, all blockchains rely on cryptography, the art and science of
encoding information so that it’s difficult to decode.
4Basic identity management—proving you are who you say you are—usually involves digital
signatures and a certificate authority. More advanced systems to manage privacy andpermissions call for more advanced cryptography.
The good news is, you don’t have to understand the intricate details of blockchains tounderstand how useful they can be.
Why blockchain matters to business people
With blockchains, many existing business processes in many industries can be streamlined
to save time, save money, and reduce risk. And many entirely new processes—perhaps evenwhole new industries—can be invented.
As the Tapscott book explains, the first generation of the Internet was great for sharing
information: things like e-mail, documents, photos, webpages, songs, and videos. But there
was a problem. It was hard for anyone to prove they were who they said they are.
Every transaction that involved any value required a middleman, like a bank or credit cardcompany, to confirm the buyer and seller and validate the transaction. That created friction,
delay, and expense—and a central point of failure that hackers could attack.
Blockchain opens the door to a second generation of the Internet much better-suited forexchanging value, including valuable information.
With blockchains, people can establish who they are and then trade items like money, stocks
and bonds, intellectual property, deeds, votes, loyalty points, and anything else that has value.
Even if the traders don’t know or trust each other, they can trust the technology to record thetransaction in a tamper-proof way. And the technology removes the need for any middleman,
which saves time and cuts costs.
Hyperledger was created to further blockchain for enterprises
Hyperledger began in 2015 when many different companies interested in blockchain
technology realized they could achieve more by working together than by working separately.
These firms decided to pool their resources and create open-source blockchain technologythat anyone could use. These far-sighted companies are helping blockchain to become amore popular and industry-standard technology.
Hyperledger was put under the guardianship of the Linux Foundation (for a host of reasonsthat we’ll talk about later) and has grown rapidly in the last few years.
As of publication date, Hyperledger has more than 230 organizations as members—from
Airbus to VMware—as well as 10 projects with 3.6 million lines of code, 10 active working
groups, and close to 28,000 participants who have come to 110+ meetups around the world.
Through 2017, the project was mentioned in the press an average of 1,500 times a month.
Those of us involved with Hyperledger think the future of blockchain will involve modular,
open-source platforms that are easy to use. With Hyperledger, we aim to create anenvironment that enables us to make this vision a reality.

5

2 Why Open Source for Blockchain?
“Proprietary software” refers to a commercial product licensed by a vendor, normally for afee. No one but the original publisher is supposed to see or touch the code. On the other
hand, open source is software that anyone can download, view, and change. This section
explains why open source makes a lot of sense for enterprise blockchains.
Open source is popular and reliable
When properly designed, coded, and deployed, open source is a proven and effective choice.
For example, the Linux operating system runs 90% of the public cloud workload, more than
80% of the world’s smartphones, and 99% of all supercomputers.2
The open source Apache web server has been the world’s most popular web server for
more than 20 years, and today supports more than 40% of all active websites.3
Other well-known open source software includes mySQL—the world’s most popular databaseserver—and the Firefox web browser.
Open source has some clear benefits
According to two recent surveys of executives and developers,4 here are the key reasons
why enterprises choose open source software:•

Competitive features and capabilities•

No vendor lock-in, so customers can easily switch•

High-quality solutions•

The ability to customize and fix bugs, through access to source code•

Lower total cost of ownership

In the early days of open source, its main attraction was that it was “free.”Today, however, enterprises choose open source to reduce risk, gain speed-to-market, andget a competitive edge. Organizations want their programmers to focus on strategic projects
that add significant value—such as building industry-specific enhancements on top of aproven platform—rather than re-inventing the wheel.
All these benefits are heightened when an enterprise confronts any profoundly new orchallenging concept—like the web in years past—and like blockchain today. Rather thandevelop an entire infrastructure and engineer all of its own solutions, enterprises can “standon the shoulders” of others who already did pioneering work and freely shared it with the world.
Open source builds trust
Blockchain represents a perfect opportunity to benefit from open source, since the conceptof trust is woven deeply into all blockchain technologies.
Blockchain systems are engineered to enable direct, peer-to-peer transactions between
parties who don’t fully trust one another, or don’t trust any central authority to validate transactions
or settle disputes. Therefore, it’s essential for these parties to trust in blockchain technologies.
We believe that an open, collaborative approach that invites participation from all stakeholders
is the most effective way to build trust for enterprises—enough trust for them to widely andrapidly adopt blockchain technologies.

6

Open governanceOpen governance means that technical decisions—such as which features to add, how to
add them, and when to add them—are made by a group of community-elected developers
drawn from a pool of active participants. Anyone can participate in Hyperledger by becoming
a contributor and/or maintainer.
Becoming a developer or maintainer translates into one thing: trust. You know how decisions
will be made and how people will be selected to make these decisions. Hyperledger isvendor-neutral and technical contributions are based on meritocracy.
Companies deploying blockchain internally, and those building products and services basedon Hyperledger projects, tell us they trust Hyperledger because our technologies are built inthe open by a broad community.
Open source promotes interoperability“Interoperable” means that a program can work with other programs—even those from otherorganizations—to quickly and easily perform a function. In today’s connected world, this is a
must-have. And in the future, we believe that many blockchains will support many businessprocesses for many organizations.
Hyperledger eases interactions between blockchains. The open source Hyperledger
technologies are designed from the start to support interoperability across various blockchains. In
particular, Hyperledger Quilt is expressly designed to support cross-chain transactions.
Open source makes sense for blockchain
Both economics and common sense are on the side of a collaborative effort like Hyperledger.
Enterprises need robust, feature-rich, modular blockchain platforms they can tailor to meettheir requirements. Businesses as diverse as banks, car and airplane makers, and healthcarecompanies make a broad ecosystem of enterprises, all cooperating with the global
Hyperledger developer community.
When many different users and vendors collaborate to co-create common technologies,
everyone can enjoy the proven benefits including lower risk, higher quality, and faster timeto-market. We believe we can do more to advance blockchain technologies by working
together than by working in isolation.

7

3 The Greenhouse for Enterprise Blockchain
Hyperledger serves as a “greenhouse” that brings together users, developers, and vendors
from many different sectors and market spaces. All these participants have one thing incommon: All are interested in learning about, developing, and using enterprise blockchains.
While blockchain is a powerful technology, it is not one-size-fits-all.
Every enterprise needs special features and modifications to help a blockchain achieve its
intended purpose. Since different organizations have different needs, there will never be
one single, standard blockchain. Instead, we expect to see many blockchains with different
features that provide a wide range of solutions across many industries.
Hyperledger provides a greenhouse structure that can incubate new ideas, support each
one with essential resources, and distribute the results widely. A greenhouse structure can
support many different varieties while consuming far fewer resources.
As the greenhouse organization for open source blockchain development, Hyperledger
provides these benefits:•

Help keeping up with developments•

Better productivity through specialization•

Collaboration to avoid duplicate efforts•

Better quality control of code•

Easier handling of intellectual property

Help keeping up with developments
Navigating through all the developments in an open source environment can be daunting. Due tothe cost and complexity involved, some organizations may give up, or never get started at all.
Hyperledger reduces this research burden by creating a collaborative environment that streamlines
communication. Better communication helps new participants to catch up, by gaining faster
access to necessary information. As newer participants quickly join the collaborative effort, thisspeeds up development for the benefit of the entire community.
Better productivity through specialization
A basic premise of economics ever since Adam Smith is that specialization—also known asdivision of labor—leads to higher productivity. Instead of everyone doing a little bit of everything,specialization enables people to focus their energies on fewer tasks and become moreexpert at them. The benefits of specialization include more expertise, more value added, andultimately more wealth created. This is why specialization has proven to be a driving factor inglobal economic development.
Participants can gain the same benefits—more expertise, more value added, and better all-aroundproductivity—by specializing in certain areas of a new technology like blockchain. In an open
source environment without any greenhouse organization, this would be far more difficult.
Hyperledger’s greenhouse structure encourages specialization, which yields better productivity.
And participants who happen to specialize in similar areas aren’t competing against eachother. In a greenhouse organization, specialists are encouraged to join forces to accelerate
their research and development.
Collaboration to avoid duplicate efforts
In a siloed environment, many people can unwittingly duplicate each another’s efforts.
Duplication of effort is especially negative in a new industry like blockchain, where the talentpool of seasoned developers is not yet deep.
8

In a greenhouse organization, collaboration between participants is highly encouraged.
This can avoid duplication, streamline the development of new projects, and encourage thecreation of common components that benefit the entire community.
Interoperability between various distributed ledgers is also enhanced by a better
understanding of other projects. And the governing structure provided by Hyperledger canhelp solve any interoperability disputes that could potentially arise.
Better quality control of code
Open source software is recognized for its high quality, achieved through careful code
reviews and significant debugging. Hyperledger promotes quality control by having atechnical governing committee review all projects throughout their life cycles. This gives
new projects a chance to be critiqued, so their developers can gain knowledge from all
the existing projects. For their part, long-time project members may discover innovations in
new projects which can enhance their own projects. This greenhouse structure also fosters
interoperability between new and existing projects.
Easier handling of intellectual property
Another benefit provided by the greenhouse structure is easier, more consistent handlingof intellectual property. Hyperledger operates under an Apache 2.0 license for code (seeapache.org/licenses/LICENSE-2.0) and Creative Commons Attribution 4.0 International
license for content (see creativecommons.org/licenses/by/4.0/). Both these licenses are
known to be especially enterprise-friendly.
A single, consistent approach to intellectual property removes the need for complex and
expensive contractual relationships among members. Since all participants have clearlycommunicated their expectations, anyone building and using Hyperledger technologies canparticipate without fear of running into hidden legal encumbrances.

FIGURE 1: THE HYPERLEDGER GREENHOUSE STRUCTURE

94 Hyperledger Design Philosophy
Distributed ledgers can have vastly different requirements for different use cases. For
instance, when participants share high levels of trust—such as between financial institutions
with legal agreements—blockchains can add blocks to the chain with shorter confirmation
times by using a more rapid consensus algrithm. On the other hand, when there is minimal
trust between participants, they must tolerate slower processing for added security.
Hyperledger embraces the full spectrum of use cases. We recognize that different enterprise
scenarios have different requirements for confirmation times, decentralization, trust, and otherissues, and that each issue represents a potential “optimization point” for the technology.
To address this diversity, all Hyperledger projects follow the same design philosophy. All our
projects must be:•

Modular•Highly secure•Interoperable•

Cryptocurrency-agnostic•

Complete with APIs

ModularHyperledger is developing modular, extensible frameworks with common building blocks
that can be reused. This modular approach enables developers to experiment with different
types of components as they evolve, and to change individual components without affecting
the rest of the system. This helps developers to create components that can be combined tobuild distributed ledger solutions well-suited to different requirements.
This modular approach also means that a diverse community of developers can work
independently on different modules, and re-use common modules across multiple projects.
The Hyperledger Architecture Working Group defines functional modules and interfaces for
issues such as communication, consensus, cryptography, identity, ledger storage, smart contracts,
and policy. To find out more, visit wiki.hyperledger.org/groups/architecture/architecture-wg.
Highly secure
Security is a key consideration for distributed ledgers, especially since many use cases
involve high-value transactions or sensitive data. With large codebases, many networked
nodes, and valuable data flows, distributed ledgers have become prime targets for online
attackers. Securing a blockchain is quite a difficult task: Distributed ledgers must provide alarge set of features and functions, while resisting persistent adversaries.
Security and robustness are the keys to enable enterprise-class blockchains to evolve, andprovide the critical infrastructure for next-generation business networks.
Hyperledger projects embrace security by design and follow the best practices specified by
the Linux Foundation’s Core Infrastructure Initiative. To find out more, visit coreinfrastructure.org/.
As such, all Hyperledger algorithms, protocols, and cryptography are reviewed and audited
by security experts, as well as the wider open source community, on a regular basis.
Interoperable
In the future, many different blockchain networks will need to communicate and exchange
data to form more complex and powerful networks. At Hyperledger, we believe that mostsmart contracts and applications should be portable across many different blockchain
10

networks. This high degree of interoperability will help meet the increased adoption ofblockchain and distributed ledger technologies.
Cryptocurrency-agnostic
Hyperledger projects are independent and agnostic of all alt-coins, cryptocurrencies, andtokens. Hyperledger will never issue its own cryptocurrency; this is decidedly not our
purpose. Hyperledger exists to create blockchain software for enterprises, not to administer
any cryptocurrency.
However, the design philosophy includes the capability to create a token used to manage
digital objects, which may represent currencies, although this is not required for the network
to operate.
Complete with APIsAll Hyperledger projects provide rich and easy-to-use APIs that support interoperability
with other systems. A well-defined set of APIs enable external clients and applications tointerface quickly and easily with Hyperledger’s core distributed ledger infrastructure. These
APIs support the growth of a rich developer ecosystem, and help blockchain and distributed
ledger technologies proliferate across a wide range of industries and use cases.

Cryptocurrency-agnostic

Interoperable

Complete with APIs
Highly Secure
Modular

FIGURE 2: THE HYPERLEDGER DESIGN PHILOSOPHY

11

5 Some Compelling Use Cases
This section describes five concrete examples where blockchain has a clear and compellinguse case.
These use cases are drawn from different domains and arranged in alphabetical order:•

Banking—applying for a loan•

Financial services—post-trade processing•

Healthcare—credentialing physicians•

IT—managing portable identities•

Supply chain management—tracking fish from ocean to table

In each case, Hyperledger has useful tools available; in some cases, a proof-of-concept has
already been developed.
5.1 Banking: Applying for a Loan
Banks want to lend, but only to borrowers who are good risks. This motivates the banks togather detailed, personally identifiable information (PII) from everyone who applies for a loan,such as date of birth, annual income, government ID or passport number, and so on.
Ultimately, the banks use this PII to access an applicant’s credit rating. Regulations may
demand that certain PII is shared with authorities, for example, to prevent money laundering.
But retaining so much PII makes every bank a juicy target for hackers.
Seeking a loan isn’t much fun for borrowers, either. The application process is intrusive, andit’s hard to “shop around” for the best rates. Every new application multiplies the effort andincreases the risk that the applicant’s PII will be abused.
HYPERLEDGER INDY CAN STREAMLINE THIS PROCESSHyperledger Indy offers a transformative identity solution for this use case.
With Indy, applicants can share only the information the banks need to make a decision, in a
way that guarantees truth, builds confidence in the lender, and satisfies pressures from regulators.
Anyone seeking a loan can apply to 100 different lenders in milliseconds, without placing any
sensitive personal data into a hackable database.
Instead of disclosing any PII, loan applicants can generate zero-knowledge proofs that they
are over 21, that their income on last year’s taxes passed a certain threshold, that they holda valid government ID number, and that their credit score met a certain threshold within thepast week.
Strong, distributed ledger-based identity establishes a global source of truth, which delivers
value to many parties. Applicants can give consent, and everyone can agree on when andhow it was given. Lenders can conform with regulations and show an immutable audit trail.
As a result, the market can operate more efficiently: Banks can offer loans with confidence,
while applicants can effectively safeguard their PII.
OTHER HYPERLEDGER PROJECTS ADD FURTHER STRENGTHSThis use case becomes even more compelling when you consider the added strengths ofother Hyperledger projects.
For example, Hyperledger Burrow can turn loan applications into smart contracts, and attach
them to strong identities as a seamless next step. And Hyperledger Fabric can drive amembership system by linking to the pre-existing, self-sovereign identity on the loan application.
125.2 Financial Services: Post-Trade Processing
The primary drivers for blockchain in today’s financial services are privacy, confidentiality,
and accountability.
Compliance guidelines like “Anti-Money Laundering” and “Know Your Customer” require thatbanks and service providers can verify a customer’s legal identity and give them clearance todo transactions. These requirements drive the adoption of permissioned and private blockchains,since public blockchains can risk compromising a participant’s privacy and confidentiality.
Together with the large volumes of transactions, these are the main reasons why consortium
blockchains are gaining momentum in financial services. Among many possible use cases inthis industry—especially in capital markets—post-trade processing can benefit from blockchain.
Today’s
Post-Trade
Processing:
Bottlenecks,
duplication ofeffort, delays

All transactions
must be reconciledat end-of-day

Post-Trade Processing
with Blockchain:No bottlenecks, noduplication, no delays

All parties see
trusted data when
they need it

FIGURE 3: POST-TRADE PROCESSING, WITH AND WITHOUT BLOCKCHAIN
THE MANY STEPS IN POST-TRADE PROCESSING

Post-trade processing includes all the activities done after a trade is completed. This covers
transactions done over-the-counter (OTC) or at an exchange.
On a high level, post-trade processing includes these steps:
1. Trade validation—Validating and confirming the transaction following the execution of
the trade.
2. Clearing—Matching the trade instructions and confirmations across the different
counterparties as well as the potential netting activities.5
3. Settlement—Legally realizing the contractual obligations to reach the finality of thetransaction. This includes support processes such as notifying all entities affected by
the transaction.
4. Custody activities—Adjusting the positions held with the custodians on behalf of thecounterparties.
5. Reporting—Satisfying all reporting requirements for regulatory and internal risk, i.e.,
the transaction’s contribution to the market and credit risk of each counterparty.

13

ISSUES WITH TODAY’S POST-TRADE PROCESSING

Today, all these steps are typically done through a fragmented workflow that spans numerous
departments across different entities: brokers, central security depositories, clearing houses,
exchanges, settlement agents, and so on. Every trade involves many different interfaces,
processes, and reconciliation efforts.
For example, today both parties send separate settlement instructions to a trusted third
party—the settlement agent—which matches both data sets and instructions. Any mismatches
trigger prolonged reconciliation efforts or may even result in a failed trade.
All this duplication of effort introduces inefficiency and delays into post-trade processing.
BLOCKCHAIN CAN STREAMLINE POST-TRADE PROCESSING

Compared to the current model, doing post-trade processing on blockchain can be far more efficient.
Leveraging the peer-to-peer strength of a blockchain, one party can insert transaction details
for the other party to verify. Doing both processes on the same system can significantly
streamline the process, since the network itself can act as a trusted third party, enabled by
the immutable and irrefutable nature of transactions on the blockchain.
The complexity can be further reduced, since all data from all steps and all actors can reside on
the blockchain, accessible on a need-to-know basis. Any further reconciliation becomes unnecessary.
And the blockchain system can also serve as an efficient basis for regulatory and trade reporting.
This means four of the five steps listed above—validation, clearing, settlement, andreporting—can be streamlined by using a blockchain for post-trade processing.6
SPECIAL FEATURES REQUIRED FOR POST-TRADE PROCESSING

Any permissioned distributed ledger can provide a tamper-proof, irrefutable transaction log.
But to be effective for post-trade processing, a blockchain requires several added features,such as immediate finality, future-proof confidentiality, and streamlined performance.
Immediate finality: Any distributed ledger used for capital markets must offer immediate
finality, so that the receiver can be assured that the transactions are valid and committed.
Consensus algorithms such as proof of work (PoW), proof of stake (PoS), or proof ofelapsed time (PoET) can cause temporary forks and even transaction rollbacks. These
are unacceptable in post-trade processing. Any blockchain for this use case must use aconsensus algorithm that provides immediate finality.
Future-proof confidentiality: Participants in any trade expect their transactions to remain
private and confidential. The clearing house recording the transaction must ensure thatparties can’t see each other’s position or trading information. Even with anonymized data,
the existence of trades must not be revealed, since this can make transactions susceptible
to traffic analysis. Correlated to public market information, this can compromise both aparticipant’s identity and their trading patterns.
In the future, even more stringent requirements for ensuring confidentiality of ledger data
may be required. In a typical blockchain where all data is stored on each participating computer,any compromise of the private key—or even worse, the cryptographic hash or encryption
algorithm—can lead to the complete unveiling of all historic data for all participants.
Any distributed ledger used for financial services must ensure that all transactions will remain
confidential for the foreseeable future.
Streamlined performance: Today, all post-trade activities happen at the end of the businessday, which presents different requirements than most other use cases. When using a
blockchain, it will not be necessary to transmit the entire day’s set of trade records to bereconciled. All trades will be reconciled in near real-time.
14

Yet the total number of transactions will likely increase, since participants can learn theirposition with the clearing house in near real-time. This means that while the average numberof transactions per second will likely increase, the peak performance requirements will
decrease significantly. Overall, system throughput will be faster.
HYPERLEDGER PROJECTS CAN HELP

Several projects from Hyperledger provide features and functions that can help build
effective blockchain solutions for post-trade processing.
The channels supported by Hyperledger Fabric can be deployed as fully disjoint networks
with separate endorser sets and ordering nodes to provide privacy and confidentiality. Restricting
data replication only to permissioned parties delivers the benefits of the blockchain for data
integrity and non-repudiation of transactions, without compromising data security. Reporting
requirements—both internal and external—can be satisfied by including a regulatory agency
and other oversight entities as members of the channel. Network segmentation enabled by
Fabric’s channels can support multiple jurisdictions and regulatory regimes.
The transaction families in Hyperledger Sawtooth provide a reliable and powerful way tosupport post-trade activities. Building complex rules using a preferred language, and exposing
only the functions appropriate to the context, enables safer smart contracts. And the option toprohibit deployment of ad-hoc smart contracts further reduces risks for financial institutions.
Hyperledger Indy’s unlinkable verifiable claims can be leveraged to report outstanding risk
on a shared ledger without compromising privacy. This still enables a regulatory body to takea holistic view of the market, and to help prevent potential market crashes and major defaults.
This feature can also strengthen privacy, by putting participants in control of their network
identities and any attributes they choose to disclose.
5.3 Healthcare: Credentialing Physicians
Blockchain technologies promise to reduce one of the great annoyances of modern medical
practice: “credentialing’’. Hospitals use the credentialing process to make sure that its
physicians are competent and trustworthy. In a sense, credentialing is the hospital’s way of
performing “due diligence’’ on a physician.
But today this process imposes a huge burden, both on the physician applying for affiliationand the hospital that must vet the applications.

1. Medical school issues tamperproof
credential on blockchain.

2. Doctor places further credentials
on blockchain.

3. Hospital validates all credentials on
blockchain, saving many steps and delays.

FIGURE 4: BLOCKCHAIN MAKES DOCTOR CREDENTIALING FASTER AND MORE SECURE

15

THE PHYSICIAN GATHERS CREDENTIALS, MANY ON PAPER

Any physician who wishes to become affiliated with a hospital begins the process bygathering copies of all their professional credentials, such as:•

Medical school diploma•

Certificates of any residencies and fellowships completed•

Certificates from any specialty medical boards•

All state medical licenses•

Evaluations from peers•

Proof of meeting requirements for continuing medical education•

Letters from hospitals where the physician was previously affiliated, explaining how
and why the affiliation ended•

Details of any malpractice suits

THE HOSPITAL CHECKS CREDENTIALS AND CALLS A MEETING

On the hospital’s side, the credentialing office checks the physician’s documentation forcompleteness, accuracy, and authenticity. This is an exacting task. Almost inevitably, they findshortfalls and go back to the doctor for missing documents.
Then the credentialing office verifies some or all of the physician’s documentation. For
example, they may phone a medical school to confirm that the physician did indeed graduate
from there. This is clearly a time-intensive process that is prone to errors.
Once the documentation is determined to be complete, accurate, and authentic, thehospital’s credentialing committee—which typically includes physicians and administrators—
meets to decide whether the physician can begin practicing in affiliation with the hospital.
The entire credentialing process is complex, low-trust, and time-consuming. And it can takeweeks or even months until any physician is cleared to affiliate with a hospital.
THREE KEY QUESTIONS FOR ANY BLOCKCHAIN SOLUTION

An effective blockchain solution for medical credentialing must answer three key questions
about content, identities, and resources.
1. Will actual content or only pointers to content be placed on the blockchain?
Credentialing solutions might place public information (such as state medical licensing)on the blockchain itself. However, private information (such as peer reviews) might bebetter stored off the chain; this would guard against any loss of keys, and enable users
to remove—but not change—private information.
2. What’s the best way to manage the identities of many participants?
An ambitious credentialing solution might include every hospital, every physician, every
source of continuing medical education, and so on. This could eventually number thousandsof participants. How will so many identities be efficiently and securely managed?
3. What resources are required, especially for storage?
Credentialing solutions may be in service for decades, requiring significant resources
for processing, communication, and storage. For example, what if at some point
credentialing organizations want video testimony from peers? Storage requirements
could skyrocket—and who would cover that added cost?

16

HYPERLEDGER CAN HELP STREAMLINE CREDENTIALING

Credentialing provides a good use case for blockchain technologies, which can simplify andstreamline every step of the process.
Hyperledger Indy provides off-the-shelf solutions that would otherwise require architecting
and developing new software. One significant feature: Indy implements the proposed W3Cstandard for verifiable claims, supporting the pairwise exchange of selected credentials. In
practice, this can work as follows:
1. A physician requests proof of graduation from their medical school.
2. After creating a pairwise relationship with the physician, the medical school sends thephysician a credential, including proof of graduation and any additional data defined.
This credential is stored in the physician’s edge device. No data from the credential
is stored on the ledger. The ledger simply holds credential definitions, public DIDs,
revocation registries, and schemas.
3. The physician can share attributes from the credential (such as proof of graduation)
as a proof for any hospital. Since all attributes in the proof are signed by the medical
school, the hospital can use the blockchain to verify the source, integrity, andrevocation status of any attribute.
4. The physician, if they choose, can use zero knowledge proofs and selective disclosure
to share only the specific data points the hospital requires, and nothing more.
This implementation of verifiable credentials safeguards the physician’s privacy, prevents
correlation, keeps personal data off the ledger, and saves time and effort for everyone
involved. At last: a better way to handle medical (or any other) credentialing.
5.4 IT: Managing Portable Identities
One of the most exciting applications of blockchain is for self-sovereign identity: the idea thatan individual owns their own “identity’’ and controls the data around it. This has profound
implications for enterprise IT.
INDY EXTENDS TRADITIONAL IDENTITY SYSTEMSHyperledger Indy is a distributed ledger with a primary focus on self-sovereign identity. Indy
shares some features with traditional enterprise identity systems such as 2FA, IDPs, LDAP,OAuth, and so on, namely:•

Industrial-strength cryptography•

Rich metadata about identities•

Sophisticated access control and policy

But there is a profound difference: Indy identities are shared, not siloed and federated. An Indy
identity is portable, so you can bring it with you wherever the distributed ledger is accepted.
This means that 10 systems that support Indy identities don’t create 10 separate identities forJohn Q. Public. Instead, all 10 systems access John’s pre-existing identity on the blockchain.
John can simply show up and use his identity. An organization can cancel John’s access, butnever his identity, because John owns it himself. And John—not the places that accept John’s
identity—controls access to his data.

17

Issues
Claim

IssuerPresents
Claim

Owner

Signs ClaimCountersigns Claim

Verifier

Verifies Signatures

Decentralized Identifiers (DIDs)
Blockchain
FIGURE 5: MANAGING PORTABLE IDENTITIES WITH BLOCKCHAIN
INDY FITS ENTERPRISE IT BETTER

Indy also shares some features with blockchain-based identity solutions such as Blockstack(blockstack.org/) and Uport (uport.me/). All these technologies store identity on a distributed
ledger to promote security and personal freedom.
However, Blockstack depends on Bitcoin and and Uport on Ethereum. These proof-of-work(PoW) ecosystems impose a high cost on transactions, so that every new persona, pairwise
relationship, published attribute, or public key rotation becomes a tangible expense. This
creates a disincentive to pairwise relationships, which undermines privacy.
Also, these ecosystems are global and public. They can’t be special-purposed for a lessthan-fully-global context.
Indy, on the other hand, does not use PoW, so that transactions are free. And different instancesof Indy can scale to fit whatever context is convenient. That makes Indy more flexible, morecost-effective, and more practical for managing identities through an enterprise blockchain.

18

5.5 Supply Chain Management: Tracking Fish from Ocean to Table
Ocean fishing represents more than $70B in worldwide trade.7 But the industry faces many problems.
For example, estimates suggest at least 20% of all fish are caught illegally—yet only a tiny
fraction are ever inspected.8
A recent study based on DNA testing found that nearly one in three fish were mislabeled bysellers.9 And a detailed sampling from 674 outlets across the United States found that 87%
of snapper and 59% of tuna were mislabelled—and worse, 95% of all sushi restaurants wereserving mislabeled fish.10
These issues create health risks for consumers, hurt vulnerable fish stocks, rob nations oftaxes, and damage the integrity of the whole industry.
MANY CHALLENGES IN SEAFOOD TRACEABILITY

Traceability and provenance are well-managed for certain local catches such as Maine
lobster and Maryland crab. But as shown in Figure 6, the complexity of the ecosystem makes
it challenging to achieve better traceability.
A recent study by the non-profit sustainable seafood organization FishWise11 identified thesekey problems:•

Many different paths from ocean to table•

Lack of global authority for tracing•

Proprietary tracing systems do not scale•

Most existing processes are paper-based

The supply chain that delivers fish from ocean to table is extremely complex and opaque. It
includes many participants from different industries, and regulatory controls that cross nationalboundaries. That makes this supply chain a perfect opportunity for blockchain technologies.
Oceana, an NGO devoted to protecting the oceans, postulated that a shared platform
for traceability would help to improve the accuracy of labeling and reduce pirate fishing:“Despite formidable challenges, seafood traceability is well within reach. Simply by keeping
track of where our seafood comes from at every step of the supply chain, we can makeprogress against pirate fishing.’’12
A SEAFOOD SUPPLY CHAIN PROTOTYPE

A team at Intel is using Hyperledger Sawtooth to build a traceability prototype that combines
the distributed ledger, IoT sensors, and advanced communications to track telemetry
parameters throughout capture, processing, and transit.
Sensors are attached to the fish when it is caught to record data such as location, temperature,and humidity. This data is recorded in the ledger, along with further events in the processingof the fish: ownership changes, storage temperature range, transport company, and so on.
The ledger can also provide analytics for both regulatory enforcement and scientific analysis
of fish harvesting and consumption.
This prototype highlights the benefits of Hyperledger Sawtooth as a platform for tracing assets.
The lightweight, highly decentralized consensus protocol in Sawtooth (proof of elapsed timeor PoET) is particularly well-suited to a diverse, distributed ecosystem where thousands ofvalidating nodes may be required. Broad participation in the ledger reflects the cross-industry
nature of the seafood supply chain.

19

FIGURE 6: THE COMPLEXITY OF THE SEAFOOD SUPPLY CHAIN
Source: Advancing Traceability in the Seafood Industry, FishWise
20

ASSET TRACKING TOUCHES ON DIFFERENT ISSUES

Asset tracking touches on several issues not generally seen in ledgers for financial products
For example, asset tracking requires handling diverse data types, such as the composite
format required for telemetry and environmental sensing.
Sawtooth accommodates both domain-specific data and the transaction families that operateon it, including data constraints such as verifying the calibration of a sensor.
Blockchain promises a number of benefits for cross-industry traceability. Most of all, thesetechnologies can help establish a community of participants and an authoritative record ofprovenance. The blockchain’s decentralized fault-tolerance enables updates from a wide range
of nodes, including fishing boats, trucks, cold-storage facilities, retail stores, and restaurants.
Beyond traceability, digitizing assets opens the door for completely new markets such as, forexample, monetization of provenance.

How It Works
1. Seafood is caught by fishermen andphysically tagged with IOT enabled sensors.
2. Sensors continuously transmit data abouttime and location to the blockchain

3. Hyperledger Sawtooth facilitates and tracks
possession changes through the distribution

4. The buyer can access a comprehensive
record of the fish’s provenance

FIGURE 7: OCEAN TO TABLE FLOWCHART USING HYPERLEDGER SAWTOOTH

21

6 Current Projects: Frameworks
Hyperledger incubates and promotes a range of business blockchain technologies, including:•Distributed ledger frameworks•

Smart contract engines•

Client libraries•

Graphical interfaces•

Utility libraries•

Sample applications

The Hyperledger strategy encourages the re-use of common building blocks, enables rapid
innovation of components, and promotes interoperability between projects.
Table 1 sums up all the current distributed ledger frameworks in alphabetical order. The restof this section sums up each framework briefly, and shows where to find more information.
Section 7 describes the current Hyperledger tools and utilities.
Table 1: Summary of Hyperledger Frameworks

HYPERLEDGERBURROW

A modular blockchain client with a permissioned smart contract
interpreter developed in part to the specifications of the
Ethereum Virtual Machine (EVM).

Covered in
Section 6.1

HYPERLEDGERFABRICA platform for building distributed ledger solutions witha modular architecture that delivers a high degree ofconfidentiality, flexibility, resiliency, and scalability. This enables
solutions developed with Fabric to be adapted for any industry.

Covered in
Section 6.2

HYPERLEDGER
INDY

A distributed ledger that provides tools, libraries, and reusable
components purpose-built for decentralized identity.

Covered in
Section 6.3

HYPERLEDGER
IROHA

A blockchain framework designed to be simple and easy toincorporate into enterprise infrastructure projects.

Covered in
Section 6.4

HYPERLEDGERSAWTOOTH

A modular platform for building, deploying, and running
distributed ledgers. Sawtooth features a new type ofconsensus, proof of elapsed time (PoET) which consumes far
fewer resources than proof of work (PoW).

Covered in
Section 6.5

6.1 Hyperledger Burrow
Hyperledger Burrow provides a modular blockchain client with a permissioned smart
contract interpreter developed partly to the specifications of the Ethereum Virtual Machine(EVM). In short, Burrow is a permissionable smart contract machine.
Burrow became the fourth distributed ledger platform within Hyperledger in April, 2017. It was
originally developed and proposed to Hyperledger by Monax.
Burrow provides a strongly deterministic, smart contract-focused blockchain design. Burrow
users benefit from an access control layer through the use of smart contracts and Äúsecure
natives-based permission layer.

22Burrow includes all the following components:•

Consensus engine—Maintains the networking stack between nodes and orderingtransactions to be used by the application engine.

•

Application Blockchain Interface (ABCI)—Provides the interface specification for theconsensus engine and application engine to connect.

•

Smart contract application engine—Provides developers with a strongly deterministic
smart contract engine for operating complex industrial processes.

•

Gateway—Provides programmatic interfaces for system integrations and user interfaces.

To find out more about Hyperledger Burrow, see hyperledger.org/projects/hyperledger-burrow.
6.2 Hyperledger FabricHyperledger Fabric is a platform for building distributed ledger solutions, with a modular
architecture that delivers high degrees of confidentiality, flexibility, resiliency, and scalability.
This enables solutions developed with Fabric to be adapted for any industry.
Fabric allows components, such as consensus and membership services, to be plug-andplay. It leverages container technology to host smart contracts called “chaincode” that
contain the business rules of the system. And it’s designed to support various pluggable
components, and to accommodate the complexity that exists across the entire economy.
Starting from the premise that there are no “one-size-fits-all’’solutions, Fabric is an extensible blockchain platform for running
distributed applications. It supports various consensus protocols,so it can be tailored to different use cases and trust models.
Fabric runs distributed applications written in general-purpose programming languages
without depending on any native cryptocurrency.
This stands in sharp contrast to most other blockchain platforms for running smart contracts, which
either require code to be written in a domain-specific language or else rely on a cryptocurrency.
Furthermore, Fabric uses a portable notion of membership for the permissioned model,
which can be integrated with industry-standard identity management. To support suchflexibility, Fabric takes a novel architectural approach and revamps the way blockchains copewith non-determinism, resource exhaustion, and performance attacks.
Fabric also can also create channels, which enable a group of participants to create a separate
ledger of transactions. This is especially important for networks where some participants
might be competitors who don’t want every transaction—such as a special price offered tosome but not all—known to every participant in the network. If a group of participants form achannel, only those participants and no others have copies of the ledger for that channel.
To find out more about Hyperledger Fabric, see hyperledger.org/projects/fabric.
6.3 Hyperledger Indy
Hyperledger Indy is a distributed ledger, purpose-built for decentralized identity. Indyprovides tools, libraries, and reusable components for creating and using independent digital
identities rooted on blockchains or other distributed ledgers.
These identities are interoperable across administrative domains, applications, and any otherorganizational silo. That means friends, competitors, and even antagonists can all rely on ashared source of truth.
Indy answers fundamental questions such as, “Who am I dealing with?” and “How can I verify
any data about the other party in this interaction?” Solid answers to these questions enable
the trusted interactions that enterprises need.
23

KEY FEATURES OF INDY•

Self-sovereignity—Indy stores identity artifacts on aledger with distributed ownership. These artifacts can
include public keys, proofs of existence, cryptographic
accumulators that enable revocation, and so on. No one but the true owner canchange or remove an identity.

•

Privacy—By default, Indy preserves privacy, since every identity owner can operate
without creating any correlation risk or breadcrumbs.

•

Verifiable claims—Identity claims can resemble familiar credentials such as birthcertificates, driver’s licenses, passports, and so on. But these can be combined andtransformed in powerful ways, using zero-knowledge proofs to enable selective
disclosure of only the data required by any particular context.

MANY POWERFUL BENEFITSThis combination of self-sovereignty, privacy, and verifiable claims is extremely powerful.
Consider the many potential benefits.
Bulk troves of sensitive data can vanish or become useless. The economics of hacking canbe transformed, since less personally identifiable information (PII) is held by each business
partner. The competing demands of preserving privacy and meeting regulations can besatisfied. Individuals and organizations can benefit from richer and more secure interactions.
And the identity ecosystem can gain the innovation and dynamism of a free market.
Despite the advanced cryptography under the hood, Indy’s API is simple and straightforward.
This API includes about 50 C-callable functions, with idiomatic wrappers for many mainstream
programming languages.
To find out more about Hyperledger Indy, see hyperledger.org/projects/hyperledger-indy.
6.4 Hyperledger Iroha
Hyperledger Iroha is a blockchain framework designed to be simple and easy to incorporate
into infrastructure projects that require distributed ledger technology.
Iroha joined Fabric and Sawtooth to become the third distributed ledger platform under
Hyperledger in October, 2016. It was originally developed by Soramitsu in Japan and was
proposed to Hyperledger by Soramitsu, Hitachi, NTT Data, and Colu.
KEY FEATURES OF IROHA:•

A simple structure•

Modern, domain-driven C++ design•

Emphasis on mobile application development•

A new, chain-based Byzantine Fault-Tolerant consensus algorithm, called Sumeragi

Iroha takes a different approach from Fabric and Sawtooth by providing features that are
helpful for creating applications for end users.
To find out more about Hyperledger Iroha, see hyperledger.org/projects/iroha.

246.5 Hyperledger Sawtooth
Hyperledger Sawtooth is a modular platform for building, deploying, and running distributed
ledgers. Distributed ledgers provide a digital record (such as asset ownership) that ismaintained without a central authority or implementation. Sawtooth aims to keep distributed
ledgers distributed and to make smart contracts safe for enterprise use. In fitting with thisenterprise focus, Sawtooth is highly modular. This enables enterprises and consortiums to
make decisions about their blockchain applications for themselves.
TECHNICAL INNOVATIONS IN SAWTOOTH

Sawtooth contains several technical innovations, including:•

Dynamic consensus—Going beyond
compile-time pluggable consensus, thisallows a consortium to change consensus
algorithms on a running blockchain simply
by issuing a transaction.

•

Proof of elapsed time (PoET)—A consensus algorithm with the scalability of proof ofwork but without the drawback of high power consumption.

•

Transaction families—A smart contract abstraction that enables users to write smart
contract logic in the language of their choosing.

•Compatability with Ethereum contracts—Transaction families can also integrateother smart contract interpreters including Hyperledger Burrow’s Ethereum Virtual
Machine. Sawtooth features like permissioning and un-pluggable consensus enable
Ethereum to be configured appropriately for an enterprise.

•

Parallel transaction execution—Most blockchains require transactions to be executedin series to guarantee consistent ordering at each peer. Sawtooth includes anadvanced parallel scheduler that splits blocks into parallel flows. Parallelism allows forfaster block processing to partially address the performance drawback of blockchainscompared to traditional databases.

•

Private transactions—Clusters of Sawtooth nodes can be easily deployed withseparate permissioning. This provides privacy and confidentiality among participants ofthat distinct chain. No centralized service leak transaction patterns or other confidential
information. However, an intermediary such as Hyperledger Quilt is required toconnect separate chains. In the future, Sawtooth plans to provide additional privacy
and confidentiality features on top of trusted execution environments and/or zeroknowledge primitives.

SAWTOOTH EXTENDS EARLIER DISTRIBUTED LEDGERS

Originally, Sawtooth was designed to explore scalability, security, and privacy questions
prompted by the earliest distributed ledgers. That required a modular design that was lacking
at the time. Starting from scratch enabled the project to draw lessons from those pioneeringsystems, and then extend into further use cases that the original currency ledgers weren’t
intended to address.
The consensus model PoET boosts scalability. Transaction families broaden the scope ofsmart contracts, while narrowing the potential attack surface. The Sawtooth designers arealso exploring trusted execution environments and the role those can play in private transactions.

25

SAWTOOTH FOR ENTERPRISES

Even when branching into new business cases, certain key features of a distributed ledger
must be preserved. In an enterprise deployment, the distributed ledger must not devolve into
nothing more than a replicated database.
Enterprise participants need autonomy and have the right to run their own nodes. This
interaction, with each member operating nodes in their own self-interest, provides theintegrity of a blockchain.
To realize that integrity, blockchains must meet three challenging requirements:
1. Provide security against malicious actors inside the network
2. Manage a large population
3. Manage a dynamic population
Many consensus algorithms used in conventional replicated databases are not designed tohandle these blockchain requirements.
Sawtooth and PoET are designed for truly decentralized blockchain applications; that
is, applications where there are many participants in the consensus process that areadministratively and physically distributed.
PoET provides security against bad actors and is designed to manage the arrival anddeparture of nodes in a large network.
Furthermore, Sawtooth provides on-chain governance to upgrade the consensus and otherbusiness rules the consortium agrees to over the life of the network. This means that a
consortium can change consensus on-the-fly using transactions only.
Users can even start with a constrained consensus and then change to a consensus like PoET
that affords the secure, dynamic, and scalable characteristics required by a production network.
To find out more about Hyperledger Sawtooth, visit hyperledger.org/projects/sawtooth.

26

7 Current Projects: Tools
Hyperledger incubates and promotes a range of business blockchain technologies, including
tools and utility libraries.
The Hyperledger strategy encourages the re-use of common building blocks, enables rapid
innovation of components, and promotes interoperability between projects.
Table 2 sums up all the current Hyperledger blockchain tools in alphabetical order.
The rest of this section sums up each tool briefly, and shows where to find more information.
Table 2: Summary of Hyperledger Tools

HYPERLEDGERCALIPERA blockchain benchmark tool that measures the performance ofany blockchain by using a set of predefined use cases.

Covered in
Section 7.1

HYPERLEDGER
CELLO

A set of tools to bring the on-demand deployment model to theblockchain ecosystem with automated ways to provision andmanage blockchain operations that reduce effort.

Covered in
Section 7.2

HYPERLEDGERCOMPOSER

An open development toolset and framework to makedeveloping blockchain applications easier.

Covered in
Section 7.3

HYPERLEDGER
EXPLORER

A dashboard for viewing information on the network, including
blocks, node logs, statistics, smart contracts, and transactions.

Covered in
Section 7.4

HYPERLEDGERQUILTA set of tools that offer interoperability by implementing ILP,
which is primarily a payments protocol designed to transfer
value across distributed and non-distributed ledgers.

Covered in
Section 7.5

7.1 Hyperledger Caliper
Hyperledger Caliper is a blockchain benchmark tool that measures the performance of any
blockchain implementation by using a set of predefined use cases.
Caliper produces reports that show a number of performance indicators, such as:•

Resource utilization•

Transaction latency•

Transactions Per Second (TPS)•

Others to be defined

Until Caliper, there has not been any general tool that provides performance evaluations fordifferent blockchain solutions, based on a set of neutral and commonly accepted rules.
Caliper will not publish benchmark results. The idea is to use Caliper as an in-house reference tohelp choose the blockchain implementation best-suited for a company’s specific needs.
Hyperledger Caliper provides a functioning benchmark tool that can run against many Hyperledger
frameworks. The community will continue to define further performance indicators andbenchmark use cases. The success of the project will depend on many community members
using it as the benchmark tool.
To see more about Hyperledger Caliper, see hyperledger.org/projects/caliper.

27

7.2 Hyperledger CelloHyperledger Cello is a blockchain module toolkit that aims to bring the on-demand
deployment model to the blockchain ecosystem. The goal is to help enterprises quickly andeasily adopt blockchain technologies, by providing automated ways to create, manage, andterminate blockchains.
Cello provides an efficient and automated multi-tenant
chain service on top of various infrastructures, including
bare metal, virtual machines, cloud platforms like Amazon
Web Services (AWS), and container platforms like Docker
Swarm and Kubernetes. All in all, this helps boost the efficiency of “Blockchain as a Service (BaaS).”
Cello also provides a real-time dashboard where users can:•View the status of the blockchain system•

See statistics such as blockchain events, chaincode performance, and system utilization•

Manage blockchains by creating, configuring, and deleting them•Manage chaincode by deploying and uploading private chaincode

Hyperledger Cello currently supports Hyperledger Fabric as the main blockchain implementation.
The project plans to support Hyperledger Sawtooth and other types of blockchains.
The architecture follows the micro-service style, with pluggable implementations for mostcomponents. The main programming languages used are Python and JavaScript.
To find out more about Cello, see hyperledger.org/projects/cello.
7.3 Hyperledger Composer
Hyperledger Composer is an open development toolset to make it simple and fast to create
smart contracts and blockchain applications to solve business problems. The main goal is tomake it easier to integrate blockchain applications with existing business systems, and thus
accelerate time-to-value.
Composer can help develop use cases and deploy
a blockchain solution in weeks, rather than months.
Composer also enables users to quickly model anexisting business network, and integrate existing
systems and data with blockchain applications. A network can contain assets—such as
tangible or intangible goods, services, or property—and transactions related to them. As partof the model, users can define how transactions can interact with assets.
Business networks include the participants who interact with them. And each participant canbe associated with a unique identity across several different business networks.
Hyperledger Composer supports the existing Hyperledger Fabric blockchain infrastructure
and runtime. Since Fabric supports pluggable consensus protocols, this ensures thattransactions can be validated according to the appropriate policy of the network participants.
To find out more about Hyperledger Composer, see hyperledger.org/projects/composer.
7.4 Hyperledger Explorer
Hyperledger Explorer provides a dashboard for viewing information about blocks, nodelogs, statistics, smart contracts, transactions, and any other information stored in theblockchain. Users can query for specific blocks or transactions to view the complete details.
Explorer can be integrated with any authentication or authorization platforms, either
commercial or open source, to provide the functions appropriate to a user’s privileges.
28

The goals of the Explorer project include:•

To create a generic web-based blockchain
explorer that’s easy to install and use withdifferent blockchain platforms•

To use the latest tools and technologies to make Explorer easy to implement, maintain,and extend•

To support the standard package managers on most popular platforms to ensure theExplorer is quick and easy to install

Hyperledger Explorer currently supports the Hyperledger Fabric framework.
To find out more about Hyperledger Explorer, see hyperledger.org/projects/explorer.
7.5 Hyperledger Quilt
Hyperledger Quilt offers interoperability between ledger systems by implementing theInterledger Protocol (ILP) in Java. ILP is a simple, open source protocol that establishes a
global namespace for accounts to help make transactions across ledgers.
MORE ABOUT THE ILP

Payment networks today are siloed and disconnected.
While payments are relatively easy within one country, or if
both the sender and recipient have accounts on the same
network or ledger, sending from one system or ledger toanother is often impossible. Where connections do exist,
they are manual, slow, or expensive.
The ILP is based on concepts dating back to the 1970s. It took the advent of Bitcoin and theglobal blockchain movement to make the world realize that money and value transfers could
be reinvented with Internet-based technologies. With ILP, money and other forms of value
can be packetized, routed, and delivered over payment networks and ledgers.
ILP is a payments protocol designed to transfer value across both distributed and nondistributed ledgers. This provides for routing payments across different digital asset ledgers,
while isolating senders and receivers from the risk of intermediary failures. Secure multi-hop
payments and automatic routing enable a global network of networks for different types ofvalue that can connect any sender with any receiver.
AN INTEROPERABILITY SOLUTION

Hyperledger Quilt is an enterprise-grade implementation of the ILP protocol, developed inJava. Quilt provides libraries and reference implementations of the core Interledger components.
The idea is that Quilt will become a ledger interoperability solution for Hyperledger projects.
This will enable the distributed ledger solutions from Hyperledger members, the private
ledgers from financial institutions, the wallets from IoT companies, and supply chain systems
to connect with one another to perform distributed atomic transactions.
By implementing the ILP, Quilt provides:•

A set of rules for enabling ledger interoperability with basic escrow semantics•

A standard for a ledger-independent address format and data packet•

A framework for designing higher-level protocols for specific use cases

To find out more about ILP, visit interledger.org/rfcs/0003-interledger-protocol/.
To see more about Hyperledger Quilt, visit hyperledger.org/projects/quilt.
29

8 Long-Term Vision
We live in a highly interconnected world. In the future, the world will no doubt become evenmore closely tied together. In both our business and personal lives, more data, more digitalcontent, more communication, and more sharing will be the norm. All this will require carefulmanagement of our security, privacy, and trust.
A common problem, and a sensible solution
We expect to see a common problem: Many people will want to share data in a distributed
database, but no single owner will be trusted by every user.
The solution is distributed ledger technology (DLT). As data sharing increases, we expect
blockchain technology and DLT to become more and more common.
But reaching widespread use of distributed ledgers will not be simple. For instance, gaining
security and privacy with a blockchain often means sacrificing performance. This suggeststhat we’ll need a variety of different blockchains that can all communicate and interact
seamlessly. No one blockchain will work best for all applications.
The long-term vision for Hyperledger is driven by two main concerns: that the architecture
must be modular and interoperable.
Interchangeable modules
We hope that eventually Hyperledger consists of many modules that can be assembled
into a cohesive, functional, and secure distributed ledger. All these modules will ideally beinterchangeable with other modules of the same type. All these modules will ideally be able
to communicate with other modules of the same or different types. And ideally, even a nonexpert will be able to use them to set up a secure, interoperable blockchain quickly, easily,and efficiently.
Many blockchains that work together
We want to specifically point out that we do not believe any Hyperledger blockchain shouldbe the “one distributed ledger to rule them all.’’ The Hyperledger community sees merit inmany different blockchains. We hope that other developers consider interoperability with
Hyperledger projects.
Not a single stack, but a collection of tools
The goal for Hyperledger is not to become a single software stack. Instead, we want tocreate a collection of tools built with modularity and interoperability in mind. Then, any
individual can use one, some, or all of the Hyperledger projects to create a distributed ledger
to suit their needs.
In the future, we hope that Hyperledger can solve most of the common problems in the
distributed ledger space. This will require a good community of developers, strong support
from business and industry, and solid design principles. As shown in this paper, we havestructured Hyperledger with all these in mind.

30

9 Conclusions
In this paper, we explained the rationale behind the creation of Hyperledger and our goals
for the project. We outlined why we think an open source greenhouse structure seems tobe the optimal governing arrangement for a general blockchain consortium. We showcasedsome of the many use cases that inspired our members to join and work on Hyperledger.
We described some of the features required to build effective blockchains for some of theseuse cases. And we briefly summed up all the Hyperledger projects and where they stand at
publication date.
We hope reading this paper is just the beginning of the Hyperledger experience for you.
We know there’s a lot of work left to be done. We realize that Hyperledger will probably always
be a work-in-progress. But—perhaps with your help—we can all work together to build secure,efficient, and reliable blockchain solutions that make a difference to everyone’s future.
Introductory sources on blockchain
Blockchain Basics: Glossary and use cases. IBM developer-Works. Updated August 21,
2017. A solid explanation of blockchain terms aimed at developers new to the space.
Blockchain Basics: A Non-Technical Introduction in 25 Steps. Daniel Drescher. Apress.
March 2017. Explains blockchain concepts with analogies, metaphors, and pictures, notmathematical formulas or program code.
Blockchain Revolution: How the Technology Behind Bitcoin Is Changing Money, Business,and the World. Don Tapscott and Alan Tapscott. Portfolio—Penguin. May 2016. Less about
the technology and more about the implications of blockchain for business. The authors also
have basic videos available on YouTube.
Blockchain Technology Overview. National Institute of Standards and Technology, U.S. Departmentof Commerce. January 2018. One of the best introductions to blockchain we have seen,
written in plain English while maintaining nuances. Includes glossary of terms and acronyms.
Further resources from Hyperledger
We encourage you to use the Hyperledger resources to find more information on any blockchainrelated topics you find interesting. Here are some further resources to get you started.
The Hyperledger Vision is a slide deck that sums up some blockchain 101-type informationand the founding vision for Hyperledger, available at hyperledger.org/resources/publications.
The Hyperledger Wiki contains a wealth of technical information, available atwiki.hyperledger.org/start.
You can find further information on each of the current Hyperledger frameworks at these links:•

Burrow—hyperledger.org/projects/hyperledger-burrow•

Fabric—hyperledger.org/projects/fabric•Iroha—hyperledger.org/projects/iroha•

Indy—hyperledger.org/projects/hyperledger-indy•

Sawtooth—hyperledger.org/projects/sawtooth

You can find further information on each of the current Hyperledger tools at these links:

31•

Caliper—hyperledger.org/projects/caliper•

Cello—hyperledger.org/projects/cello•Composer—hyperledger.org/projects/composer•

Explorer—hyperledger.org/projects/explorer•

Quilt—hyperledger.org/projects/quilt

The Hyperledger Working Groups have many great technical resources, and are open toanyone with an interest in their subjects. For example, the Architecture Working Group has
substantial documentation on the fundamentals of permissioned blockchain. If you’re looking
to explore technical details, that group is a great resource.
The application-specific working groups are also great places to learn. For instance, theIdentity Working Group has spent a lot of time discussing and documenting how blockchain
can enable identity solutions.

32

Notes
1. Don Tapscott and Alan Tapscott. Blockchain Revolution: How the Technology Behind
Bitcoin Is Changing Money, Business, and the World. Portfolio-Penguin. 2016. p9
2. 2017 State of Linux Kernel Development.
linuxfoundation.org/2017-linux-kernel-report-landing-page/
3. April 2018 Web Server Survey. Netcraft.
news.netcraft.com/archives/2018/04/26/april-2018-web-server-survey.html
4. The 10th Annual Future of Open Source Survey. North Bridge and Black Duck
Software. 2016. blackducksoftware.com/2016-future-of-open-source
5. Note that the counterparty risk arising between concluding and settling a trade,typically two or three days, can be reduced if the counterparties have agreed on
bilateral margining or if the transactions are cleared through a clearing house.
6. The usefulness of blockchain for post-trade settlement may be limited, since near realtime settlement may eliminate the netting benefits (position offsetting) of end-of-day
processing.
7. Food and Agriculture Organization, United Nations. 2016. The State of World
Fisheries and Aquaculture 2016. fao.org/3/a-i5555e.pdf
8. Stolen Seafood: The Impact of Pirate Fishing on Our Oceans. Oceana. 2013.
oceana.org/sites/default/files/reports/Oceana_StolenSeafood.pdf
9. Miguel Ángel Pardo, Elisa Jiménez, Begoña Pérez-Villarreal. Misdescription incidents
in seafood sector. 2016. Food Control 62 pages 277–283.
10. Oceana Study Reveals Seafood Fraud Nationwide. 2013.
oceana.org/sites/default/files/reports/National_Seafood_Fraud_Testing_Results_
FINAL.pdf
11. FishWise. 2017. Advancing Traceability in the Seafood Industry: Assessing
Challenges and Opportunities. https://fishwise.org/wp-content/
uploads/2018/04/2018.02.22_Trace-WP_February-2018-Update-1.pdf
12. Oceana. 2014 Annual Report. oceana.org/sites/default/files/2014_annual_report.pdf

33