---
title: "Concepts"
description: "Learn more about the general building blocks of decentralized ID solutions."
stack: "Concepts (stack-agnostic, applies to both Community and Enterprise Stack)"
stack_comparison: https://docs.walt.id/community-vs-enterprise.md
canonical_url: https://docs.walt.id/concepts
generated: 2026-07-08
---
# Concepts

Learn more about the general building blocks of decentralized ID solutions.

- [Decentralised Identity](https://docs.walt.id/concepts/decentralized-identity.md) - An introduction to decentralized identity.
- [ID Ecosystems](https://docs.walt.id/concepts/id-ecosystems.md) - The role of ecosystems in decentralized ID solutions.
- [Decentralised Identifiers (DIDs)](https://docs.walt.id/concepts/decentralised-identifiers.md) - The role of DIDs and how they work.

### Digital Credentials
Learn more about the different types of digital credentials

- [Verifiable Credentials (W3C)](https://docs.walt.id/concepts/digital-credentials/verifiable-credentials-w3c.md) - The W3C data model for tamper-evident digital credentials.
- [mDL / mdoc credentials](https://docs.walt.id/concepts/digital-credentials/mdoc-mdl-iso.md) - ISO/IEC 18013 mobile driver's license and mdoc credential format.
- [SD-JWT VC credentials](https://docs.walt.id/concepts/digital-credentials/sd-jwt-vc.md) - JWT-based credentials with selective disclosure for claim-level privacy.
- [Mono claim credentials](https://docs.walt.id/concepts/selective-disclosure/mono-claim-credentials) - Single-attribute credentials for minimal disclosure and simple verification.

### Credential Exchange Protocols

- [OpenID4VCI (Issuance)](https://docs.walt.id/concepts/data-exchange-protocols/openid4vci.md) - Protocol for issuing verifiable credentials to wallets.
- [OpenID4VP (Presentation)](https://docs.walt.id/concepts/data-exchange-protocols/openid4vp.md) - Protocol for presenting credentials from a wallet to a verifier.
- [Digital Credentials API (Browser-Based)](https://docs.walt.id/concepts/data-exchange-protocols/dc-api.md) - W3C browser API that mediates credential presentation and issuance natively in the browser also known as DC API.
- [HAIP (High Assurance Profile)](https://docs.walt.id/concepts/data-exchange-protocols/haip.md) - Security-hardened profile of OpenID4VCI and OpenID4VP for high-assurance interoperability. Required by eIDAS 2.

### Trust Systems

- [EU Trust Lists](https://docs.walt.id/concepts/trust-systems/eu-trust-lists.md) - Machine-readable registries of trusted entities for the EU digital identity ecosystem (eIDAS 2.0).
- [ISO mDL Trust / VICALs](https://docs.walt.id/concepts/trust-systems/iso-trust-vicals.md) - Certificate authority hierarchies for verifying ISO mobile document issuers.
- [Wallet Attestations](https://docs.walt.id/concepts/trust-systems/wallet-attestations.md) - Cryptographic proofs that establish the authenticity and integrity of digital wallets.

### Credential Lifecycle

- [Credential lifecycle](https://docs.walt.id/concepts/credential-lifecycle/credential-status-and-revocation.md) - How to manage the status (e.g. revocation) of credentials.