computer science

Self-sovereign identity

Self-sovereign identity is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Self-sovereign identity rather than just read about it. In short: Self-sovereign identity (SSI) is an approach to digital identity that gives individuals control over the information they use to prove who they are to websites, services, and applications across the web. Without SSI, individuals with persistent accounts (identities) across the internet must rely on a number of large identity providers, such as Facebook (Facebook Connect) and Google (Google Sign-In), that have contro…

Key takeaways

Self-sovereign identity belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Self-sovereign identity to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Self-sovereign identity from memory before moving on to harder problems.

Reference excerpt

Self-sovereign identity (SSI) is an approach to digital identity that gives individuals control over the information they use to prove who they are to websites, services, and applications across the web. Without SSI, individuals with persistent accounts (identities) across the internet must rely on a number of large identity providers, such as Facebook (Facebook Connect) and Google (Google Sign-In), that have control of the information associated with their identity. If a user chooses not to use a large identity provider, then they have to create new accounts with each service provider, which fragments their web experiences. Self-sovereign identity offers a way to avoid these two undesirable alternatives. In a self-sovereign identity system, the user accesses services in a streamlined and secure manner, while maintaining control over the information associated with their identity. SSI systems are commonly built upon Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs). DIDs provide decentralized, cryptographically verifiable identifiers that enable secure authentication without centralized registries, while verifiable credentials allow trusted issuers to attest to specific claims about an identity subject. These credentials can be presented and verified cryptographically, often without direct interaction with the issuer at the time of verification.

Background The TCP/IP protocol provides identifiers for machines, but not for the people and organisations operating the machines. This makes the network-level identifiers on the internet hard to trust and rely on for information and communication for a number of reasons:

Hackers can easily change a computer’s hardware or IP address. Services provide identifiers for the user, not the network. The absence of reliable identifiers is one of the primary sources of cybercrime, fraud, and threats to privacy on the internet. With the advent of blockchain technology, a new model for decentralized identity emerged in 2015. The FIDO Alliance proposed an identity model that was no longer account-based, but identified people through direct, private, peer-to-peer connections secured by public/private key cryptography. Self-Sovereign Identity (SSI) summarises all components of the decentralized identity model: digital wallets, digital credentials, and digital connections.

Technical aspects SSI addresses the difficulty of establishing trust in an interaction. In order to be trusted, one party in an interaction will present credentials to the other parties, and those can verify that the credentials came from an issuer that they trust. In this way, the verifier's trust in the issuer is transferred to the credential holder. This basic structure of SSI with three participants is sometimes called "the trust triangle". It is generally recognized that for an identity system to be self-sovereign, users control the verifiable credentials that they hold, and their consent is required to use those credentials. This reduces the unintended sharing of users' personal data. This is contrasted with the centralized identity paradigm where identity is provided by some outside entity. In an SSI system, holders generate and control unique identifiers called decentralized identifiers. Most SSI systems are decentralized, where the credentials are managed using crypto wallets and verified using public-key cryptography anchored on a distributed ledger. The credentials may contain data from an issuer's database, a social media account, a history of transactions on an e-commerce site, or attestation from friends or colleagues.

Blockchain account standards Some blockchain identity systems use smart contracts as accounts with attachable data and permissions. ERC-725 is a draft Ethereum standard for smart-contract accounts with generic data storage and execution. LUKSO's Universal Profiles apply this model to on-chain profiles, combining a recoverable smart-contract account with public profile data for decentralized applications.

National digital identity systems

European Union

The European Union is exploring decentralized digital identity through a number of initiatives including the International Association for Trusted Blockchain Application (INATBA), the EU Blockchain Observatory & Forum and the European SSI Framework. In 2019, the EU created an eIDAS compatible European Self-Sovereign Identity Framework (ESSIF). The ESSIF makes use of decentralized identifiers (DIDs) and the European Blockchain Services Infrastructure (EBSI).

Korea The Korean government created a public/private consortium specifically for decentralized identity.

Germany In the German and European legal area, there are two regulations that are of particular importance for the topic. These include the eIDAS Regulation, which forms the most important framework for trust in electronic identification in the EU and is a fundamental building block of the digital single market. The European Blockchain Service Infrastructure (EBSI) has provided the SSI eIDAS Bridge, as a technical implementation that enables a substantial level of trust. The eIDAS SSI legal report also describes several scenarios of how SSI can fulfill the necessary regulatory conditions. Furthermore, the General Data Protection Regulation (GDPR) forms the legal basis for the handling of personal data. The EBSI GDPR Legal Report provides more information on this.

Concerns

Implementation and semantic confusion SSI is a value laden technology whose technical operationalizations differ (see Technical aspects). Therefore, its implementations can vary significantly and embed into the very technology different goals, agenda, and intentions. The term "self-sovereign identity" can create expectations that individuals have absolute control and ownership over their digital identities, akin to physical possessions. However, in practice, SSI involves complex technical infrastructure, interactions with identity issuers and verifiers, and compliance with legal frameworks. The reality may not align with the perception generated by the term, leading to semantic confusion.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Self-sovereign identity

Start with the simplest possible case. Write down what Self-sovereign identity claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Self-sovereign identity before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Self-sovereign identity ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Self-sovereign identity

In research: Self-sovereign identity appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Self-sovereign identity in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Self-sovereign identity is common in secondary-school and first-year university syllabi. It links to neighbouring topics Authentication methods, Computer access control, Digital technology, so understanding it makes those chapters shorter.
In everyday life: Look for Self-sovereign identity outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Self-sovereign identity in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Self-sovereign identity means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Self-sovereign identity out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Self-sovereign identity in simple terms?

Why does Self-sovereign identity matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Self-sovereign identity?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Self-sovereign identity.