---
title: "Trust Systems"
description: "Understanding trust infrastructure in digital identity ecosystems including EU Trust Lists, ISO mDL trust mechanisms, and wallet attestations"
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/trust-systems
generated: 2026-07-20
---
# Trust Systems

Trust systems are the foundational infrastructure that enables secure, verifiable interactions in digital identity ecosystems. They answer the critical question: *"How do I know I can trust this entity?"*

## Why Trust Systems Matter

In decentralized identity ecosystems, parties that have never met must be able to:

- **Verify credentials** – Confirm that a credential was issued by a legitimate authority
- **Authenticate wallets** – Ensure wallet applications are genuine and secure
- **Establish authority** – Determine which entities are authorized to issue specific credentials
- **Enable interoperability** – Support cross-border and cross-jurisdictional recognition

Trust systems provide the technical and governance infrastructure to make these verifications possible at scale.

## Core Concepts

### Trust Anchors

A trust anchor is a cryptographic public key (and associated metadata) that serves as the root of trust for verifying other entities. Trust anchors are typically:

- Published in trusted lists or registries
- Managed by authoritative bodies (governments, standards organizations)
- Used to verify certificate chains and credential signatures

### Trust Lists

Trust lists are authoritative, machine-readable registries of trusted entities. They enable automated verification by providing:

- Public keys and identifiers for trusted entities
- Status information (active, suspended, revoked)
- Metadata about entity capabilities and authorizations

### Attestations

Attestations are cryptographic proofs that vouch for specific properties of an entity, such as:

- Wallet application integrity
- Key storage security
- Compliance with standards or regulations

## Trust Systems in This Section

This section covers three major trust system approaches used in digital identity:

### [EU Trust Lists](https://docs.walt.id/concepts/trust-systems/eu-trust-lists.md)

The European Union's standardized trust infrastructure for the EUDI Wallet ecosystem, based on ETSI standards and mandated by eIDAS 2.0. Covers:

- National Trusted Lists and the EU List of Trusted Lists (LoTL)
- Trust anchors for Wallet Providers, PID Providers, and Attestation Providers
- ETSI TS 119 612 format and implementation

### [Trust in ISO mDL: VICALs and IACAs](https://docs.walt.id/concepts/trust-systems/iso-trust-vicals.md)

The trust infrastructure defined by ISO/IEC 18013-5 for mobile driver's licenses and mobile documents. Covers:

- Issuing Authority Certificate Authorities (IACAs)
- Verified Issuer Certificate Authority Lists (VICALs)
- Reader authentication mechanisms
- Regional implementations (AAMVA, Austroads)

### [Wallet Attestations](https://docs.walt.id/concepts/trust-systems/wallet-attestations.md)

Cryptographic proofs that establish trust in digital identity wallets. Covers:

- Wallet Instance Attestations (WIA)
- Key Attestations and Wallet Trust Evidence (WTE)
- Integration with OpenID4VCI
- Platform-specific attestation mechanisms

## Comparison of Trust Approaches

| Aspect | EU Trust Lists | VICAL (ISO 18013-5) | Wallet Attestations |
|--------|---------------|---------------------|---------------------|
| **Primary Purpose** | Ecosystem-wide trust | mDL issuer verification | Wallet integrity |
| **Scope** | EU Member States | Regional (per VICAL) | Per wallet instance |
| **Format** | XML (ETSI) | CBOR/COSE | JWT/COSE |
| **Governance** | European Commission | Regional bodies | Wallet Providers |
| **Update Frequency** | Periodic publication | Versioned refresh | Per-instance lifecycle |

## Further Reading

- [ID Ecosystems](https://docs.walt.id/concepts/id-ecosystems.md) – Overview of identity ecosystem components
- [Data Exchange Protocols](https://docs.walt.id/concepts/data-exchange-protocols.md) – How credentials are exchanged
- [Credential Lifecycle](../6.credential-lifecycle/) – Issuance, verification, and revocation