#About Validator

The validator is a core service in the Vidos ecosystem that validates digital credentials and presentations according to relying party requirements and organizational policies. It ensures that credentials meet specific business requirements, come from trusted issuers, and satisfy presentation constraints from the perspective of the relying party, providing a critical trust layer for acceptance workflows.

#Why use a Validator?

In digital trust ecosystems, validation is essential for establishing confidence in credentials before accepting them. The Validator provides:

• Relying party validation of digital credentials against configurable acceptance policies
• Trusted issuer verification ensuring credentials come from issuers trusted by your organization
• Presentation compliance verifying that credential presentations meet specific requirements
• Format validation ensuring credentials conform to expected structures and standards
• Standardized results that clearly indicate validation status and any issues

By automating the complex validation process from the relying party's perspective, the Validator enables applications to make informed acceptance decisions without needing to implement complex validation logic.

#What is a Validator?

A validator functions as a trusted validation service that assesses whether digital credentials and presentations meet the relying party's acceptance criteria. It processes input credentials or presentations and returns detailed validation results that indicate whether the credential should be accepted based on the relying party's requirements.

The Validator performs multiple policy checks including:

• Format validation - Ensuring credentials conform to expected data models and structures
• Trusted issuer verification - Confirming credentials come from issuers trusted by the relying party
• Presentation compliance - Verifying that credential presentations meet specific requirements and constraints
• Schema validation - Validating that credentials conform to acceptance schemas defined by the relying party
• Business rule validation - Applying custom validation policies based on organizational requirements

#Validator Architecture

The Validator in Vidos has two main components that work together to provide validation services:

1. Validator Service: The core implementation that handles the validation process according to configurable policies
2. Validator Management Service: Enables configuration and management of validator instances for different validation needs

Vidos supports creating multiple validator instances, each with its own policy configuration, to support different validation requirements within your organization.

The Validator works closely with other Vidos services:

• Receives cryptographically verified credentials from the Verifier service
• Interacts with the Resolver to retrieve issuer information for trust validation
• Provides validation results to the Authorizer for access control decisions

#Validation Process

When a credential is submitted for validation, the Validator performs a series of policy checks from the relying party's perspective:

1. Format validation - Confirms the credential follows expected data structures and standards
2. Trusted issuer verification - Validates that the issuer is trusted by the relying party
3. Presentation compliance - Ensures presentations meet specific requirements and constraints
4. Schema validation - Verifies credentials conform to acceptance schemas
5. Business rule validation - Applies custom validation policies configured for the relying party
6. Constraint checking - Validates that all presentation constraints are satisfied

Each check can be individually configured or disabled to meet specific validation requirements.

#Supported Standards

The Validator supports multiple industry standards for comprehensive validation:

• W3C Verifiable Credentials Data Model v1.1 and v2.0
• ISO/IEC 18013-5 (mDL - mobile Driver's License)
• IETF Digital Credential specification
• DIF Presentation Exchange specification
• Digital Credential Query Language (DCQL)

#Use Cases

The Validator Service supports various validation scenarios:

• Credential acceptance - Validate that credentials meet relying party requirements before acceptance
• Presentation validation - Ensure presentation submissions satisfy specific constraints
• Issuer trust verification - Confirm credentials come from trusted sources
• Compliance validation - Ensure credentials meet regulatory and organizational requirements
• Multi-format validation - Support different credential formats through a unified interface

By providing configurable validation policies, the Validator Service enables customized acceptance decisions based on your organization's specific requirements while maintaining focus on validating that the credential meets the relying party's trust and business requirements.

#Summary

The Validator is a critical service in the Vidos ecosystem that:

• Validates credentials and presentations from the relying party's perspective
• Applies configurable validation policies to support diverse acceptance requirements
• Verifies trusted issuer relationships and presentation compliance
• Provides clear, structured validation results for making acceptance decisions
• Integrates with other Vidos services to enable comprehensive trust solutions

By offering standardized validation capabilities focused on relying party requirements, the Validator simplifies the implementation of trusted credential acceptance across your applications and services.