#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

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

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

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

#Further Reading

• ID Ecosystems – Overview of identity ecosystem components
• Data Exchange Protocols – How credentials are exchanged
• Credential Lifecycle – Issuance, verification, and revocation