An agent, in the context of self-sovereign identity, acts as a delegate of an individual identity; holds cryptographic keys to prove this responsibility; and interacts with other agents.
Reference: https://github.com/hyperledger/aries-rfcs/tree/master/concepts/0004-agents
Decentralized identifiers (DIDs) are a new type of identifier that enables verifiable, decentralized digital identity. A DID identifies any subject (e.g., a person, organization, thing, data model, abstract entity, etc.) that the controller of the DID decides that it identifies.
Reference: https://www.w3.org/TR/did-core/
This refers to the general idea about how agents communicate with each other.
Reference: https://github.com/hyperledger/aries-rfcs/tree/master/concepts/0005-didcomm#motivation
A set of data describing the DID subject, including mechanisms, such as public keys and pseudonymous biometrics, that the DID subject or a DID delegate can use to authenticate itself and prove its association with the DID. A DID document may also contain other attributes or claims describing the DID subject.
Reference: https://www.w3.org/TR/did-core/#dfn-did-documents
Also known as a prover, a holder is the entity to whom an issuer issues a credential. Although the holder can request or propose that a credential be issued to them, they may not always be the subjects of a credential.
In the PresentProof flow, the prover prepares the proof and presents it to the verifier.
The entity that issues a credential to a holder.
This stands for Key Management Service and is responsible for securely storing sensitive agent information such as private keys, secrets and other private data.
Reference: https://github.com/hyperledger/aries-rfcs/tree/master/concepts/0440-kms-architectures
A mediator is a participant in agent-to-agent message delivery. It can be seen as a router with mailbox features which cannot read the encrypted contents of the routed messages.
An interface for verifying data against a trusted backing store such as a ledger or a database. A role a system might perform by mediating the creation and verification of relevant data which might be required to use verifiable credentials.
Reference: https://www.w3.org/TR/vc-data-model/#dfn-verifiable-data-registries
A verifiable credential can represent all of the same information that a physical credential represents. It is a tamper-evident credential that has authorship that can be cryptographically verified. Examples of verifiable credentials include digital employee identification cards, digital birth certificates, and digital educational certificates.
Reference: https://www.w3.org/TR/vc-data-model/#what-is-a-verifiable-credential
A verifiable presentation expresses data from one or more verifiable credentials, and is packaged in such a way that the authorship of the data is verifiable.
Reference: https://www.w3.org/TR/vc-data-model/#presentations
This is the entity who makes a request for a credential or proof from a holder and verifies it.
Reference: https://github.com/hyperledger/aries-rfcs/tree/master/features/0454-present-proof-v2#roles