Architecture

The system architecture follows the C4 model (Context, Containers, Components, and Code) to provide a clear hierarchical view of the solution’s structure. The diagrams distinguish between existing components (color gray) and the new components that CHECK provides (color blue).

The following C4 system and container diagrams provide a comprehensive view of our solution’s architecture, showing how the various components interact to create a cohesive trust enhancement framework for e-commerce.

System Context Diagram

The System Context Diagram illustrates the highest-level view of the CHECK verification solution and its relationship with external entities. It shows how CHECK fits into the broader e-commerce ecosystem and identifies the primary actors and systems that interact with it.

Customer represents the end-users who visit web shops with the intention to browse and purchase products or services. They seek trustworthy shopping experiences where they can confidently engage with verified retailers without fear of fraud or misrepresentation.

These individuals interact directly with the verification interface during their shopping journey, making trust signals a critical factor in their purchase decisions. While shoppers benefit from increased confidence in their online transactions, they also play an active role in the bidirectional trust model by providing their own credentials for verification when required, particularly for high-value transactions or when establishing new commercial relationships.

Retailer encompasses web shops seeking to establish credibility with potential customers. They integrate the CHECK verification system into their e-commerce platform, provide business credentials for verification, and implement the customer verification components within their transaction flow. Their active participation in both directions of the trust verification model is essential for the system’s effectiveness and value creation.

Container Diagram

The architecture includes four core components: Embedded Verification Interface, Verification Service Interface, Verification Service, and Verifiable Data Service.

The comprehensive demo web shop demonstrates end-to-end integration of all primary components within a realistic e-commerce environment.

Verification Service

Functionality: Serves as the core verification engine, authenticating web shops through their Decentralized Identifiers (DIDs) via publicly accessible Verifiable Credentials. The service discovers DID-URL connections and performs cryptographic verification of credential authenticity according to configured trusted issuers and schemas. The Verification Service Interface provides a stand-alone user interface alongside the Embedded Verification Interface.

Technologies: Implemented in Rust programming language utilizing SpruceID’s SSI Library for standards-compliant credential processing, with Axum web framework providing high-performance HTTP service capabilities. The Verification Service Interface is using SolidJS framework and the Solid-Start framework for providing server rendering capabilities. For deployment packaging both components utilize NixOS for reproducible builds with Docker containerization.

Status: Complete implementation featuring comprehensive verification functionality, including support for external DID resolvers, DIF Well-Known DID Configuration specification compliance, and DIF Linked Verifiable Presentationi specification implementation.

Embedded Verification Interface

Functionality: Provides the primary user-facing verification display, presenting web shop verification status as integrated trust marks while enabling visitors to inspect retailers’ published Verifiable Credentials. This component serves as the critical user touchpoint for verification results within existing web shop interfaces. The component depends on the Verification Service and is embedded as a JavaScript and CSS bundle within existing web shops.

Technologies: Built using SolidJS framework packaged through NixOS and Docker for consistent deployment across diverse hosting environments.

Status: Complete UI implementation emphasizing accessibility and usability principles derived from comprehensive user experience research and iterative design refinement.

Verifiable Data Service

Functionality: Operates as a secure temporary data transmission service for customer-provided Verifiable Credentials during transaction processes.

Technologies: Rust implementation leveraging SpruceID’s SSI Library for credential processing and SpruceID’s OpenID4VC Library for wallet interoperability, with NixOS and Docker packaging ensuring consistent deployment.

Status: Complete implementation including full OpenID4VP protocol support enabling seamless integration with EUDI-compatible wallets and other standards-compliant credential wallets.