Infominer and Kaliya “Identity Woman” Young

Self-sovereign identity grew out of a decade-long movement widely known as user-centric identity, of which Kaliya “Identity Woman” Young is one of the most distinguished pioneers. Kaliya started the Internet Identity Workshop (IIW) in 2005 with Doc Searls and Phil Windley. Held twice every year since then, IIW has been the birthplace of almost every major innovation in decentralized digital identity. As SSI has grown, it has attracted newcomers such as Infominer, a prolific (and anonymous) SSI writer and curator, coached by Kaliya (who has always supported bringing more talent into the community). Together, they have co-founded Identosphere.net. In this chapter, the two of them describe the fascinating evolution of the SSI community from its origins to the present. Obviously, this will need to be updated over time, but we hope this chapter gives you a broad perspective on where the SSI movement has come from and why it has gained so much attention.

The term self-sovereign identity (SSI) grew from a 2012 blog post by Devon Lofretto to the VRM (vendor relationship management) mailing list. The post was titled “Sovereign Source Authority” [1]. Since then, SSI has grown into the banner of an ecosystem of communities, organizations, tools, and specifications aiming to put users in control over their digital identifiers and personal information. The quest for SSI is a journey of community awareness and organization—of building and promoting the use of tools and frameworks that empower users—and the gradual warming of the world to a cause that, ironically, embraces some of the same core values that led to the development of the internet itself.

16.1 The birth of the internet

From the very beginning, the system underlying the internet has relied on a centralized Internet Assigned Numbers Authority (IANA) for the assignment of identifiers used in the operation of the internet. IANA has handed down authority to other central authorities, such as the Internet Corporation for Assigned Names and Numbers (ICAAN) and certificate authorities (CAs).

note See the 1990 RFC “IAB Recommended Policy on Distributing Internet Identifier Assignment and IAB Recommended Policy Change to Internet ‘Connected’ Status,” https://tools.ietf.org/html/rfc1174.

From 1972 until 1989, “Jake” Elizabeth Feinler [2] was the director of the Network Information Systems Center at the Stanford Research Institute. Her group ran the Network Information Center (NIC) for the ARPANET as it became the Defense Data Network (DDN) and later the internet.

Jake was a volunteer at the Computer History Museum, where the Internet Identity Workshop (IIW) began meeting in 2006. Seeing the agenda at one of our first meetings there, she asked if it was an ICANN meeting and stayed to share about her team creating the first namespace system convention.

—Kaliya “Identity Woman” Young

At first, centralized agencies were required to manage the assignment of identifiers online. They have continued to operate in such a fashion, in part because once empowered, organizations are reluctant to relinquish that power—and in part due to the many other challenges of creating widely accepted and interoperable decentralized solutions. But the internet was always designed to be decentralized, and now pioneers in cryptography have opened the way for it to become even more so (see chapter 13 for more about this).

16.2 Losing control over our personal information

The inventor of blind signatures and “Father of digital currency,” David Chaum, was among the first to discuss how individuals were losing control over the way our personal information is used. Chaum’s proposed solution involved creating a unique digital pseudonym with each party we transact. As he described it [3]:

Large-scale automated transaction systems of the near future can be designed to protect the privacy and maintain the security of both individuals and organizations.

Chaum made it clear that such a system would put users in control over their identity—as opposed to using a token created by a third party, whom users then had no choice but to entrust with the management of their personal information.

Chaum might well be thought of as the “grandfather of SSI.” (He can also be designated the grandfather, among others, of digital cash, blockchain, and cryptocurrency technologies, as described in chapters 13 and 17.) His work inspired a generation about the potential to create novel cryptographic systems and privacy-preserving applications.

Soon after Chaum came Roger Clarke, who introduced the term dataveillance. In 1988, he defined it as follows [4]:

The systematic monitoring of people’s actions or communications through the application of information technology.

Clarke expresses the need for laws to safeguard personal privacy and states that IT professionals must strive to create applications that preserve their users' privacy.

16.3 Pretty Good Privacy

After World War II, many government agencies prohibited the distribution of secure encryption schemes. For example, in the United States, encryption was treated as a munition, and exporting it was illegal. As a result, businesses were required to use weak encryption for international products, which for practical business reasons meant they often had to use the same weak encryption for their domestic products.

In response to the growing danger of losing our right to personal privacy, Phil Zimmerman created Pretty Good Privacy (PGP) in 1991 [5]. His thought was that if strong encryption became widespread, it would be difficult for the government to criminalize.

The release of PGP marked the first time in history that strong encryption became available to the general public. PGP’s public key cryptography, and Zimmerman’s concept of the web-of-trust [6] provided an early foundation for self-sovereign identity. Unfortunately, PGP had a reputation of being difficult to use, and thus it failed to achieve wide adoption for the encryption of personal communications. However, the early popularity of PGP demonstrated that the same values that inspired the academic world of cryptography and computer science in the early 1970s were still alive and well and leading to innovative new technologies and events.

16.4 International Planetwork Conference

In May 2000, the first International Planetwork Conference (https://planetwork.net/about.html) was held in San Francisco, with the theme of Global Ecology and Information Technology. This conference (held again in 2003 and 2004; see https://web.archive.org/web/20060714223112/http://www.planetwork.net/2004conf) and the community that developed around it planted the seeds of much that followed. The conversation that began at that first conference continued informally through 2001, when it became known as LinkTank (https://planetwork.net/linktank.html), a group seeking to create and maintain “a digital communications platform, operated as a public interest utility.”

The XNS Public Trust Organization (XNS.org) was founded in July 2000, shortly after Planetwork, to promote individual ownership of digital identity and personal data based on Extensible Resource Identifier (XRI) and Extensible Data Interchange (XDI), open standards contributed to OASIS by OneName Corporation. (See https://web.archive.org/web/20011101021136/http://www.onename.com [unrelated to BlockstackOnename].)

In 2001, the Identity Commons, led by Owen Davis and Andrew Nelson, joined forces with XNS.org to promote XRI and XDI as the basis of an identity layer of the internet. They worked with Cordance and Neustar to create Extensible Name Services (https://icannwiki.org/XDI.org), which sought to instill an element of trust between people and the new data-sharing networks. It had a centralized global registry for human-readable names, iNames, that would be paired with a namespace of never-recycled identifiers called iNumbers.

note Cordance (https://web.archive.org/web/20120117204002/http://www.cordance.net) created the technology under the development of the XRI and XDI Oasis Technical Committees. Neustar (https://www.home.neu star) is a telecommunications company originally charged with maintaining the system of directories and databases for telephone area codes and prefixes in North America.

16.5 Augmented Social Network and Identity Commons

In 2003, Ken Jordan, Jan Hauser, and Steven Foster published The Augmented Social Network: Building Identity and Trust into the Next-Generation Internet [7], born from ideas developed through Planetwork and LinkTank. The Augmented Social Network (ASN) sought to build a persistent online identity into the architecture of the internet—giving users complete control over their identity.

Following the June 2004 Planetwork conference, Kaliya Young began working as an evangelist and community builder with Identity Commons. She collaborated with Doc Searls and Phil Windley of the Social Physics team, led by Paul Trevithick and Mary Ruddy, to weave together a community of like-minded individuals scattered across the country.

This community, focused on user-centric identity, first came together at the Digital Identity World conference in the fall of 2004. That meeting resulted in the creation of a mailing list (https://lists.idcommons.net/lists/info/community); and that December, over the holidays, Doc Searls invited a number of identity leaders to appear together on the Gilmore Gang podcast. That’s where the name Identity Gang was coined; and with the encouragement of Doc Searls, a number of people began blogging about user-centric identity.

16.6 The Laws of Identity

Among those bloggers was Kim Cameron, chief architect of identity at Microsoft, who published the Laws of Identity [8]. He implored us to build systems where users were in full control over how their personal information was exposed, for that exposure to be minimal, and for it to be shared only with parties having a justifiable need for it. He also postulated that individuals should be difficult to correlate across services, while at the same time identity technologies should be interoperable between identity providers.

Between Kim’s blog, other blogs, and the community mailing list, there was a robust sharing of ideas and technical paths toward achieving them. Among all these quite different leaders, Paul Trevithick took the lead in creating the Identity Gang Lexicon (see https://web.archive.org/web/20080916112039/wiki.idcommons.net/Lexicon).

16.7 Internet Identity Workshop

In the fall of 2005, the mailing list organized a community gathering in the Bay Area at the Hillside Club in Berkeley. It was called the Internet Identity Workshop (IIW, https://web.archive.org/web/20060720180524/http://www.socialtext.net:80/iiw2005 /index.cgi?internet_identity_workshop_2005), and it was co-produced by Kaliya Young, Doc Searls, and Phil Windley.

The first day was a regular-style conference, with each of the eight different user-centric ID systems/paradigms presenting. On the second day, Kaliya facilitated an unconference (http://unconference.net) supporting the co-creation of its agenda by attendees. That was where Yadis (Yet Another Digital Identity Interoperability System) was born [9]. Led by Johannes Ernst [10], Yadis was a decentralized system to enable interoperability between dominant identity schemes of the time.

16.8 Increasing support of user control

Over the years that followed, IIW facilitated the creation of technologies that increasingly supported user control of our identities, starting with OpenID, OAuth, System for Cross-domain Identity Management (SCIM), Information Cards, and later Fast IDentity Online (FIDO), User-Managed Access (UMA), and OpenID Connect. In 2010, Markus Sabadello began Project Danube (https://web.archive.org/web/20101221105543/http://projectdanube.org) to work on the creation of an XDI-based personal data store that always remains under the control of its users. From that point on, an array of emerging companies began to work on personal data stores, user-centric identity, and other tools to manage personal data and identifiers. In 2011, Kaliya founded the Personal Data Ecosystem Consortium (http://pde.cc/) to connect them.

Respect Network was founded around the same time; its architects included Drummond Reed, Markus Sabadello, and Les Chasen. Their goal was to create a cloud environment for the secure management of personal data. Members of the Respect Network were governed by the five principles of the award-winning Respect Trust Framework (https://respectnetwork.wordpress.com/respect-trust-framework):

These five principles can be summed up by “the 5 p’s” in one sentence: A promise of permission, protection, portability, and proof.

16.9 Rebooting the Web of Trust

In 2014, Manu Sporny of Digital Bazaar proposed the formation of a Credentials Community Group at the W3C (https://www.w3.org/community/credentials/) to explore the creation of common standards for a decentralized system of credentials. This marked the beginning of a new era for decentralized identity.

In the fall of 2015, Christopher Allen announced a new type of event—a “design workshop”—devoted to the topic of how blockchain technology could enable the long-sought goals of user-centric identity. The first event was called the Rebooting the Web of Trust (RWoT). These design workshops support small groups working together intensively for a few days to produce key pieces of collaborative work.

RWoT participants work on white papers, specifications, pieces of code—all around creating next-gen, decentralized, web-of-trust based identity systems. The first RWoT workshop [11] facilitated nearly 50 topic papers and advance readings contributed by its participants and produced five completed white papers, including the following:

• “Opportunities Created by the Web of Trust for Controlling and Leveraging Personal Data” by du5t, Kaliya “Identity Woman” Young, John Edge, Drummond Reed, and Noah Thorp (https://github.com/WebOfTrustInfo/reboot ing-the-web-of-trust/blob/master/final-documents/satisfying-real-world-use-cases.pdf). This seminal paper began with the following paragraph:

Today, decentralized Webs of Trust remain as important as ever. Now is the time to extend them to be usable by everyone who has access to digital networks ... from marginalized persons like stateless refugees and victims of human trafficking to members of the informal or unregulated economy—urgently need to participate in otherwise privileged economic and political fora, but they face technical, economic, and political barriers to entry.

• “Decentralized Public Key Infrastructure” by Christopher Allen, Arthur Brock, Vitalik Buterin, Jon Callas, Duke Dorje, Christian Lundkvist, Pavel Kravchenko, Jude Nelson, Drummond Reed, Markus Sabadello, Greg Slepak, Noah Thorp, and Harlan T Wood (https://github.com/WebOfTrustInfo/rwot1-sf/blob/mas ter/final-documents/dpki.pdf). This paper put a stake in the ground for what is turning out to be one of the most important uses of blockchain technology, as described in the opening paragraph:

Today’s Internet places control of online identities into the hands of third-parties. ... This paper describes a possible alternate approach called decentralized public key infrastructure (DPKI), which returns control of online identities to the entities they belong to.

By this point, ConsenSys had begun working on uPort, an Ethereum- and IPFS-based solution for self-sovereign identity, which was initially described at DEVCON1 by Christian Lundkvist (November, 2015) [12].

16.10 Agenda for Sustainable Development and ID2020

The United Nations Agenda for Sustainable Development was published toward the end of 2015 and included 19 sustainable development goals (SDGs). SDG 16.9 was “To provide legal identity for all by 2030.” To this end, the World Bank founded Digital IDs for Development (ID4D, http://www.worldbank.org/en/events/2015/06/23/digital-ids-for-development) to work “leveraging digital identities (IDs) as part of a unified system to better deliver services and benefits to people, especially the poor and the disadvantaged.” The early work of ID4D was largely aligned with centralized identity management paradigms and vendors who provide tools to nation-states.

After learning that “one of the biggest problems in protecting children who are at risk of sexual violence is a lack of birth certificates or identity” [13], John Edge was inspired by the possibility of using blockchain to issue self-sovereign identities to those with no official capacity to acquire one. John helped to found the first ID2020 Summit, an event aligned with SDG 16.9 “legal identity for all,” held at UN headquarters in New York. ID2020 is a nonprofit public-private partnership that seeks solutions for the 1.1 billion people without any officially recognized identification (see https://datacatalog.worldbank.org/dataset/identification-development-global-dataset).

Christopher Allen, who was part of the team organizing ID2020, published “The Path to Self Sovereign Identity” [14], outlining the Principles of Identity (see https://github.com/WebOfTrustInfo/self-sovereign-identity/blob/master/self-sovereign-identity-principles.md) building from Cameron’s Laws of Identity, the Respect Trust Framework, and the Verifiable Claims Working Group (http://w3c.github.io/webpay ments-ig/VCTF/charter/faq.html).

The Second Rebooting Web of Trust workshop was held in conjunction with ID2020 and was hosted by Microsoft and facilitated by Kaliya Young. This was the workshop where the initial decentralized identifier (DID) white paper was completed. Notable output from this workshop included the following:

• “Requirements for DIDs” by Drummond Reed and Les Chasen (Respect Network; https://github.com/WebOfTrustInfo/rwot2-id2020/blob/master/final -documents/requirements-for-dids.pdf). DIDs are a common standard for self-controlled, privacy-respecting identifiers that enable individuals and organizations across the globe to connect and communicate securely (see chapter 8). This document was inspired by the principles of the XDI.org Registry Working Group to seek maximum interoperability, decentralization, neutrality, and sovereign identity. It was the first in a series about producing a concrete DID system aligned with the goals of the W3C Credentials Community Group.

• “Identity System Essentials” by Samuel Smith and Dmitry Khovratovich (https://github.com/WebOfTrustInfo/rwot2-id2020/blob/master/topics-and-advance -readings/Identity-System-Essentials.pdf). This was the initial white paper from Evernym, a startup focused entirely on self-sovereign identity.

In addition to their paper discussing the needs of an identity system, Evernym had begun working on a public-permissioned blockchain for self-sovereign identity that later would become the Sovrin ledger.

16.11 Early state interest

In the spring of 2016, the U.S. Department of Homeland Security (DHS) awarded $100,000 Small Business Innovation Research contracts to four companies focused on the “Applicability of Blockchain Technology to Identity Management and Privacy Protection.” These contracts included one to Digital Bazaar to study the feasibility of developing a flexible standard for distributed ledgers to support DIDs and verifiable credentials to fulfill the needs of DHS use cases (https://www.sbir.gov/sbirsearch/detail/1241085) and one to Respect Network to “research and develop a decentralized registry and discovery service for Decentralized Identifiers (DIDs) to integrate with the public blockchain” (https://www.sbir.gov/sbirsearch/detail/1241097)

In August 2016, the Digital Identity and Authentication Council of Canada (DIACC) published the “Pan-Canadian Trust Framework Overview” (described in detail in chapter 23; https://diacc.ca/wp-content/uploads/2016/08/PCTF-Overview -FINAL.pdf), a collaborative approach to defining interoperable digital identity that would work across all of Canada’s provinces and beyond. It said,

A trust framework consists of a set of agreed definitions, requirements, standards, specifications, processes and criteria. The set of agreed details enable identity management process and authorization decisions carried out by other organizations and jurisdictions to be relied on with a standardised level of confidence.

16.12 MyData and Learning Machine

MyData (http://mydata2016.org) was founded in August 2016 to provide a legal structure for an international movement promoting the rights of individuals to control our personal information. In September 2016 [15], Phil Windley announced the formation of the Sovrin Foundation to promote the creation of a decentralized identity layer for the internet using the codebase for a public-permissioned ledger developed by Evernym. Soon after, Evernym’s acquisition of Respect Network (see https://pitch book.com/profiles/company/53867-44) heralded what has proved to be a powerful joining of forces.

By this point, Learning Machine had been working with MIT for about a year to develop an open standard for blockchain credentials. Led by Chris Jagers, Kim Hamilton Duffy, and John Papinchak, their Blockcerts prototype was released in October [16].

Joe Andrieu continued the discussion of self-sovereign identity principles in “A Technology-Free Definition of Self Sovereign Identity” [17] submitted to the third RWoT Workshop in San Francisco. As this paper put it,

To fund, co‐develop and eventually deploy a global self‐sovereign solution to UN Sustainable Development Goal 16.9, it would be prudent to begin with an explicit requirements process independent of any specific technology.

In light of UN SDG 16.9, Andrieu detailed three core characteristics for SSI:

1. Users should have control over their identity information.

2. The credentials should be accepted as widely as possible.

3. Their cost should be as low as possible.

16.13 Verifiable Claims Working Group, Decentralized Identity Foundation, and Hyperledger Indy

In April 2017, the charter for the Verifiable Claims Working Group was approved at the W3C [18]. Chaired by Daniel Burnett of ConsenSys and digital identity expert Matt Stone, its purpose was to develop a standard for machine-readable personal information that would be verified by a third party on the web. Verifiable credentials could include any form of digitally signed data including banking information, educational records, healthcare data, and other forms of personally identifiable machine-readable data.

At Consensus 2017, a leading global blockchain conference, Microsoft, uPort, Gem, Evernym, Blockstack, and Tierion announced the formation of the Decentralized Identity Foundation (DIF, http://identity.foundation). DIF’s goal was to collaboratively develop the foundational components of an open, standards-based, decentralized identity ecosystem for people, organizations, apps, and devices.

In May 2017, the Hyperledger initiative at the Linux Foundation announced the introduction of the Sovrin codebase into its family of open source tools and frameworks for blockchain technology. This new project was given the name Hyperledger Indy [19]. Finally, in July 2017, Digital Bazaar began working to create Veres One (https://github.com/veres-one), a public permissionless blockchain fit for purpose to support a decentralized identity network.

16.14 Increasing state support for SSI

In July 2017, as a result of work accomplished by Respect Network and Digital Bazaar since their preliminary funding, the DHS SBIR awarded each company an additional $749,000 for Phase 2 contracts:

• Evernym’s contract was “to design and implement a decentralized key management system (DKMS) for blockchain technologies based on National Institute of Standards and Technology Special Publication 800-130, A Framework for Designing Key Management Systems” [20].

• Digital Bazaar’s contract was “to develop a flexible software ecosystem that combines fit-for-purpose distributed ledger technology, digital credentials and digital wallets to address a wide variety of identity management and online access use cases for the Homeland Security Enterprise (HSE)” [21].

In 2013, the Canadian Province of British Columbia, which has a long history of digital identity innovation, launched a citizen services card with a triple-blind backend database. In September 2017, it announced detailed plans to build tools to support the creation of publicly verifiable credentials for businesses in the province via the Verifiable Organizations Network (VON; see https://archive.org/details/TBSIdentityPolicy Workshop).

16.15 Ethereum identity

Jolocom originally began in 2002 as a project to help companies communicate and share information among themselves. In August 2017, Jolocom announced its efforts to create an Ethereum-based SSI application and smart wallet [22].

In October 2017, Fabian Vogelsteller began work on ERC 725, describing proxy smart contracts that can be controlled by multiple keys and other smart contracts (https://github.com/ethereum/eips/issues/725). ERC 735 is an associated standard to add claims to and remove them from an ERC 725 identity smart contract. These identity smart contracts can describe humans, groups, objects, and machines.

16.16 World Economic Forum reports

At the start of 2018, the World Economic Forum (WEF) published “The Known Traveller—Unlocking the Potential of Digital Identity for Secure and Seamless Travel” [23], which promoted the use of a distributed ledger, with no central authority, for digital identity. It also highlighted Sovrin, uPort, and Blockcerts as examples of self-sovereign identity technologies that are vendor-agnostic and support user control.

On May 25, 2018, the General Data Protection Regulation (GDPR) was enacted into law across the European Union. In development since 2015, this legislation shifts ownership of customer data from organizations to individuals and applies to anyone doing business with European citizens. To remain compliant, an identity system must support privacy by design and privacy by default. The GDPR represents the first time there has been data protection legislation so strongly aligned with SSI principles.

In September 2018, the WEF published “Identity in a Digital World: A New Chapter in the Social Contract” [24]:

It outlines what we’ve learned to date on what user-centricity means and how to uphold it in practice. It attempts to offer a shared working agenda for leaders: an initial list of immediate-term priority actions that demand cooperation.

16.17 First production government demo of an SSI-supporting ledger

On September 3, 2018, the ERC 725 Alliance formed to promote the development of Ethereum standards supporting SSI [25]. A few days later, on September 10, the Government of British Columbia’s Verifiable Organization Network went into production [26]. VON makes it easier for public organizations to apply for credentials, simplifies issuance, and “makes verifying credentials more standard, trustworthy, and transparent—anywhere in the world.”

Also in September 2018, Microsoft unveiled “Decentralized Identity: Own and Control Your Identity,” a white paper about joining a diverse community to build an open and interoperable, standards-based DID solution for individuals and organizations [27].

16.18 SSI Meetup

In early 2018, Alex Preukschat, with initial support from Evernym, created SSI Meetup (https://ssimeetup.org) to be an open, independent, collaborative community to help SSI evangelists worldwide. SSI Meetup hosts regular webinars that are shipped with extensive infographics—pre-labeled with a Creative Commons license for ease of sharing. SSI Meetup has become a widely shared educational resource for the SSI community.

16.19 Official W3C standards

One of the most significant milestones in the evolution of SSI was the final approval, in September 2019, of the W3C Verifiable Credentials Data Model 1.0 specification. For the SSI community, this heralded the official beginning of the world’s recognition of SSI as a new model for digital identity on the internet. Not coincidentally, the same month marked the official announcement of the establishment of the W3C Decentralized Identifier (DID) Working Group with a two-year charter to take DIDs to the same level of official W3C standard. DIDs are the first identifier to enter the full Working Group standardization process at the W3C since the adoption of the HTTP and HTTPS URLs at the dawn of the web.

16.20 Only the beginning

Those in the SSI community feel that the tide has truly turned for those seeking to create an internet-wide identity layer. In addition to regulatory support from the GDPR, systems for decentralized identity are now being developed to meet the needs of the U.S. Department of Homeland Security, Canadian governments (both federal and provincial), a public/private partnership called Findy in Finland (https://www.findy.fi), a similar national project in Germany called SSI4DE (https://www.snet.tu-berlin.de/menue/projects/ssi4de), and the UN SDGs. Corporations such as Microsoft, IBM, Mastercard, Cisco, and Accenture have joined forces with blockchain consortia such as Ethereum Enterprise Alliance, Hyperledger, and the Sovrin Foundation to create SSI networks that can serve people, organizations, and things worldwide.

Our community is in active evolution. The best way to dive into our diverse community and learn more is to attend one of the workshop events where these systems are actively being co-created. The IIW continues every six months in Mountain View, California (www.internetidentityworkshop.com); and RWoT continues worldwide twice a year (www.weboftrust.info).

There are several other regular conferences where SSI is a major topic, including these:

• MyData —Building a global community of people who want control of their data along with the companies working on making it happen (https://mydata.org)

• ID2020 —Helping bring sustainable digital identity to the 1.1 billion people in the world without a legal identity (https://id2020.org)

• Identity North —A series of events for individuals and organizations interested in Canadian digital identity and the digital economy (https://www.identitynorth.ca)

• The European Identity Conference —Europe’s oldest and most respected digital identity conference (https://www.kuppingercole.com/events/eic2021)

SSI Resources For more free content to learn about SSI, please go to IdentityBook.info and SSI Meetup.org/book.

References

1. Lofretto, Devon. 2012. “What Is “Sovereign Source Authority?” The Moxy Tongue. https://www .moxytongue.com/2012/02/what-is-sovereign-source-authority.html.

2. Weber, Marc. 2009. Interview: “Oral History of Elizabeth (Jake) Feinler.” Computer History Museum. https://web.archive.org/web/20110811175249/http://archive.computerhistory.org/resources/access/text/Oral_History/102702199.05.01.acc.pdf.

3. Chaum, David. 1985. “Security Without Identification: Transaction Systems to Make Big Brother Obsolete.” Communications of the ACM 28 (10): 1030. https://www.cs.ru.nl/~jhh/pub/secsem/chaum1985bigbrother.pdf.

4. Clarke, Roger. 1988. “Information Technology and Dataveillance.” Communications of the ACM 31 (5): 498-512, http://www.rogerclarke.com/DV/CACM88.html.

5. Zimmerman, Philip. 1991. “Why I Wrote PGP.” https://www.philzimmermann.com/EN/essays/WhyIWrotePGP.html.

6. Ryabitsev, Konstantin. 2014. “PGP Web of Trust: Core Concepts Behind Trusted Communication.” https://www.linux.com/learn/pgp-web-trust-core-concepts-behind-trusted-communication.

7. Jordan, Ken, Jan Hauser, and Steven Foster. 2003. “The Augmented Social Network: Building Identity and Trust into the Next-Generation Internet.” First Monday 8 (8). https://firstmonday.org/ojs/index.php/fm/article/view/1068.

8. Cameron, Kim. 2009. “7 Laws of Identity.” Kim Cameron’s Identity Weblog. https://www.identityblog .com/?p=1065.

9. Windley, Phil. 2005. “Yet Another Decentralized Identity Interoperability System.” Technometria. http://www.windley.com/archives/2005/10/yet_another_dec.shtml.

10. Ernst, Johannes. 2009. “From 1 to a billion in 5 years. What a little URL can do.” Upon 2020. https://upon2020.com/blog/2009/12/from-1-to-a-billion-in-5-years-what-a-little-url-can-do.

11. Galt, Juan. 2015. “Andreas Antonopoulos: The Case Against Reputation and Identity Systems.” Bitcoin.com. https://news.bitcoin.com/andreas-antonopoulos-case-reputation-identity-systems.

12. ConsenSys. 2015. “The Identity Crisis.” https://medium.com/@ConsenSys/identity-is-defined-in-merriam-s-dictionary-as-who-someone-is-a3d6a69f5fa4.

13. Jordan, Gina. 2016. “Projects Aim for Legal Identity for Everyone.” SecureIDNews. https://www.secureidnews.com/news-item/projects-aims-for-legal-identity-for-everyone.

14. Allen, Christopher. 2016. “The Path to Self-Sovereign Identity.” Life with Alacrity. http://www .lifewithalacrity.com/2016/04/the-path-to-self-soverereign-identity.html.

15. Windley, Phil. 2016. “Announcing the Sovrin Foundation.” Technometria. http://www.windley .com/archives/2016/09/announcing_the_sovrin_foundation.shtml.

16. Jagers, Chris. 2016. “Verifiable Credentials on the Blockchain.” Learning Machine. https://medium.com/learning-machine-blog/blockchain-credentials-b4cf5d02bbb7.

17. Andrieu, Joe. 2016. “A Technology-Free Definition of Self Sovereign Identity.” https://github .com/WebOfTrustInfo/rwot3-sf/blob/master/topics-and-advance-readings/a-technology-free -definition-of-self-sovereign-identity.pdf.

18. Jia, Xueyuan. 2017. “Verifiable Claims Working Group Charter Approved; join the Verifiable Claims Working Group (Call for Participation).” W3C. https://lists.w3.org/Archives/Public/public-vc-wg/2017Apr/0000.html.

19. Sovrin Foundation. 2017. “Announcing Hyperledger Indy.” https://www.cuinsight.com/press-release/announcing-hyperledger-indy-purpose-built-decentralized-independent-identity-individ uals-enterprise.

20. Department of Homeland Security. 2017. “DHS S&T Awards $749K to Evernym for Decentralized Key Management Research and Development.” https://www.dhs.gov/science-and-technol ogy/news/2017/07/20/news-release-dhs-st-awards-749k-evernym-decentralized-key.

21. Department of Homeland Security. 2017. “DHS S&T Awards $750K to Virginia Tech Company for Blockchain Identity Management Research and Development.” https://www.dhs.gov/science -and-technology/news/2017/09/25/news-release-dhs-st-awards-750k-virginia-tech-company.

22. Lohkamp, Joachim.2017. “Jolocom: Who Owns and Controls Your Data?” https://stories.jolo com.com/jolocom-who-owns-and-controls-your-data-effc7bc02ee8.

23. World Economic Forum. 2018. “The Known Traveller—Unlocking the Potential of Digital Identity for Secure and Seamless Travel.” http://www3.weforum.org/docs/WEF_The _Known_Traveller_Digital_Identity_Concept.pdf.

24. World Economic Forum. 2018. “Identity in a Digital World: A New Chapter in the Social Contract.” https://www.weforum.org/reports/identity-in-a-digital-world-a-new-chapter-in-the-social -contract.

25. Bennett, George. 2018. “Introducing the ERC-725 Alliance.” https://medium.com/erc725 alliance/introducing-the-erc725-alliance-2fe0682e3515.

26. Jordan, John, and Stephen Curran. 2018. “A Production Government Deployment of Hyperledger Indy.” Decentralized Identity. https://decentralized-id.com/government/canada/bcgov/von/hgf-2018-production-government-deployment-hyperledger-indy/.

27. Microsoft. 2018. “Decentralized Identity: Own and Control Your Identity.” https://query.prod .cms.rt.microsoft.com/cms/api/am/binary/RE2DjfY.