Self Sovereign Identity (SSI) is an umbrella term well-detailed by Christopher Allen, and inspired by many in the Identity community before him, in his 2016 blog post: The Path to Self-Sovereign Identity, which identifies Ten Principles of Self-Sovereign Identity:
Existence. Users must have an independent existence.Control. Users must control their identities.Access. Users must have access to their own data.Transparency. Systems and algorithms must be transparent.Persistence. Identities must be long-lived.Portability. Information and services about identity must be transportable.Interoperability. Identities should be as widely usable as possible.Consent. Users must agree to the use of their identity.Minimalization. Disclosure of claims must be minimized.Protection. The rights of users must be protected.