Credentials
A set of one or more claims made by an issuer.
Source: W3C Verifiable Credential Data Model
Decentralized Identifiers (DIDs)
A portable URL-based identifier, also known as a DID, associated with an entity. These identifiers are most often used in a verifiable credential and are associated with subjects such that a verifiable credential itself can be easily ported from one repository to another without the need to reissue the credential. An example of a DID is did:example:123456abcdef.
Source: W3C Verifiable Credential Data Model
DID Methods
DIDs are not created and maintained in a single type of database or network like many other types of URIs. There is no authoritative centralized registry — or a hierarchy of federated registries like DNS — where all DIDs are written and read. Many different types of DIDs exist in today’s SSI community. They all support the same basic functionality, but they differ in how that functionality is implemented, e.g. how exactly a DID is created or where and how a DID’s associated DID document is stored and retrieved.
These different types of DIDs are known as DID methods. The second part of the DID identifier format — between the first and second colons — is called the DID method name.
Example of DIDs created using five different DID methods
did:sov:WRfXPg8dantKVubE3HX8pw— Sovrin (sov).did:btcr:xz35-jzv2-qqs2-gwjt— Bitcoin (btcr).did:v1:test:nym:3AEJTDMS×DDOpyUftiuoeZ2Bazp4Bswilce7FJGYbcUu— Veres One (v1).did:ethr:OXE6Fe788d8ca214A080b0f6aC7F48480b2AEfa9a6— Ethereum (ethr).did:iolo:1fb352353f51248C5104b407f9c04c3666627fcf5a167d693c9fc84675964e2— Jolocom (jolo).
Source: Self-Sovereign Identity: Decentralized digital identity and verifiable credentials
Entity
A thing with distinct and independent existence, such as a person, organization, or device that performs one or more roles in the ecosystem.
Source: W3C Verifiable Credential Data Model
Holder
A role an entity might perform by possessing one or more verifiable credentials and generating presentations from them. A holder is usually, but not always, a subject of the verifiable credentials they are holding. Holders store their credentials in credential repositories.
Source: W3C Verifiable Credential Data Model
Issuer
A role an entity can perform by asserting claims about one or more subjects, creating a verifiable credential from these claims, and transmitting the verifiable credential to a holder.
Source: W3C Verifiable Credential Data Model
JSON Schema
A declarative language that allows you to annotate and validate JSON documents.
Source: Verifiable Credentials JSON Schema Specification
Verifiable Credentials (VCs)
A tamper-evident credential that has authorship that can be cryptographically verified.
Source: W3C Verifiable Credential Data Model
Verifiable Credential JSON Schema
A JSON Schema usage for the validation of W3C Verifiable Credentials, where the JSON Schema is contained with a verifiable credential.
Source: Verifiable Credentials JSON Schema Specification
Verifiable Data Registry (VDR)
A role a system might perform by mediating the creation and verification of identifiers, keys, and other relevant data, such as verifiable credential schemas, revocation registries, issuer public keys, and so on, which might be required to use verifiable credentials. Some configurations might require correlatable identifiers for subjects. Some registries, such as ones for UUIDs and public keys, might just act as namespaces for identifiers.
Source: W3C Verifiable Credential Data Model
Verifiable Presentations (VPs)
Data derived from one or more verifiable credentials, issued by one or more issuers, that is shared with a specific verifier. A verifiable presentation is a tamper-evident presentation encoded in such a way that authorship of the data can be trusted after a process of cryptographic verification. Certain types of verifiable presentations might contain data that is synthesized from, but do not contain, the original verifiable credentials (for example, zero-knowledge proofs).
Source: W3C Verifiable Credential Data Model
Verifier
A role an entity performs by receiving one or more verifiable credentials, optionally inside a verifiable presentation for processing. Other specifications might refer to this concept as a relying party.
Source: W3C Verifiable Credential Data Model
Self-Sovereign Identity (SSI)
Self-sovereign identity — commonly abbreviated SSI — is a new model for digital identity on the internet: i.e., how we prove who we are to the websites, services, and apps with which we need to establish trusted relationships to access or protect private information.
Source: Self-Sovereign Identity: Decentralized digital identity and verifiable credentials
Wallet
A program that stores and protects access to holders' verifiable credentials.