Self-sovereign identity (SSI) is an approach to digital identity that gives individuals control of their digital identities. This concept intends to give individuals ownership of their data and who can access which parts of their identity.
SSI addresses the difficulty of establishing trust in interaction and personal data privacy.
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.
You can read more on Wikipedia at: https://en.wikipedia.org/wiki/Self-sovereign_identity#:~:text=Self%2Dsovereign%20identity%20(SSI),establishing%20trust%20in%20an%20interaction.