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SSI | Basics

Learn what SSI is and how it works.

What is SSI?

Self-Sovereign Identity (SSI) is a user-centric approach to digital identity that gives people and organizations full control over their data. As a result, SSI enables anyone to easily share their data and reliably prove their identity (i.e. who they are and anything about them) without sacrificing security or privacy.
In other words, SSI enables you to “bring your own identity” and this is true for potentially any type of information - from your core identity (e.g. name, age, address) to your education and work records, your health and insurance data, bank account and financial information, etc.
Moreover, SSI can be used to model the digital identities of people, organizations and things.
At the end of the day, SSI promises a digital world in which interactions are effortless and worry-free. It is simply the next evolutionary step in identity management, a new paradigm in which our digital identities are no longer fragmented and locked into silos that are under someone else’s control, but only at our own disposal to be shared securely and privately.

How does SSI work?

SSI allows us to model digital identity just like we are used to the way identity works in the non-digital world based on paper documents and cards. There are just some minor twists.
For example, instead of our identity documents being made of paper or plastic, they are digital credentials made of bits and bytes and instead of storing them in wallets made of leather, they are stored in digital wallets on our phones. Importantly, these digital credentials can be reliably verified by anyone they are shared with online or offline.
In doing so, SSI enables decentralized ecosystems in which different parties can exchange and verify identity-related information. These ecosystems look like three-sided marketplaces, so that every party can take on three roles:
  • Issuers - Parties who “issue” identity-related data to people or organizations (“Holders”) in the form of digital credentials. They are the original data sources of an SSI ecosystem. For example, a government issues digital passports to citizens or a university issues digital diplomas to graduates.
  • Holders - Individuals or organizations who receive digital credentials that contain data about themselves from various sources (“Issuers”). By aggregating and storing such credentials in digital wallets, Holders can build holistic digital identities that are under their control and can easily be shared with third parties ("Verifiers").
  • Verifiers - Parties who rely on data to provide products and services can reliably verify and process data that has been provided by others (“Holders”). Verifiers, also called “Relying Parties”, are usually organizations or individuals in their professional capacity.
Usually, a single party plays only one of these roles per interaction. However, it is perfectly normal for a party to take on different roles in different interactions.
For example:
  • A university (Holder) is being accredited to issue certain types of educational credentials by a national authority (Issuer).
  • A university (Issuer) issues a digital diploma to a graduate (Holder), who can share this information with a recruiter (Verifier) in the course of a job application.
  • After the recruiting process, a recruiter (Issuer) issues the results of an applicant’s assessment (e.g. skills, referral) to the applicant (Holder), who can share this information with a new manager or another recruiter (Verifier).
  • A manager (Issuer) issues the results of a performance review to his employee (Holder) who can share this information with HR (e.g. to improve talent development programs).