CDN: Content Delivery Network for EUDI Wallet Infrastructure

A Content Delivery Network (CDN) is a distributed network of proxy servers and data centers deployed across multiple geographic locations. CDNs serve content to users from the nearest edge location, dramatically reducing latency and improving reliability. For the EUDI Wallet ecosystem, CDNs are essential infrastructure components that ensure credential verification services, revocation endpoints, and trust framework resources are accessible quickly and reliably across the entire European Union.

When a user or service requests a resource, the CDN routes that request to the nearest edge server rather than the origin server, which might be hundreds or thousands of kilometers away. The edge server either serves the content from its cache (a cache hit) or fetches it from the origin server and caches it for future requests (a cache miss).

CDNs use several techniques to optimize delivery. DNS-based routing directs users to the closest Point of Presence (PoP). Anycast networking allows multiple servers to share the same IP address, with the network automatically routing to the nearest one. Cache invalidation mechanisms ensure that when content changes at the origin, edge caches are updated promptly.

Modern CDNs go beyond simple caching. They offer edge computing capabilities, allowing lightweight processing at edge nodes. They provide built-in DDoS mitigation, rate limiting, and Web Application Firewall (WAF) functionality. For EUDI services, these security features are just as valuable as the performance benefits.

The EUDI Wallet ecosystem generates several types of traffic that benefit from CDN distribution:

• •Certificate Revocation Lists (CRLs): CAs publish CRLs that wallets and verifiers download periodically. These are relatively small files that change infrequently, making them ideal CDN candidates. Caching CRLs at edge locations ensures wallets can check revocation status quickly, even during peak demand.
• •Credential Schemas and Metadata: Verifiers need to download credential schemas to understand the structure of presented credentials. Trust framework metadata, including EU Trusted Lists, must be accessible to all participants. CDNs distribute these files efficiently across the continent.
• •Web Verification Portals: Many EUDI Wallet interactions happen through web interfaces -- for example, online age verification or identity proofing for banking. CDNs serve the static assets (HTML, CSS, JavaScript) for these portals, ensuring responsive user experiences regardless of the user's location.
• •Wallet App Updates: Over-the-air updates for EUDI Wallet mobile applications can be distributed through CDNs, enabling rapid deployment of security patches across millions of devices simultaneously.

Importantly, CDNs never cache or handle actual credential data or personal information. The presentation of verifiable credentials happens through direct, encrypted peer-to-peer or client-server connections. CDNs handle only the supporting infrastructure that makes these interactions fast and reliable.

A critical consideration for EUDI infrastructure CDNs is data sovereignty. Under GDPR and the eIDAS 2.0 framework, there are strict requirements about where data can be processed and stored. CDN providers serving EUDI infrastructure must ensure that:

• •All edge nodes serving EU traffic are physically located within EU/EEA countries
• •No cached data is replicated to servers outside the EU without explicit authorization
• •Access logs and analytics comply with GDPR data minimization principles
• •The CDN provider itself meets applicable EU security certification requirements

Several European CDN providers and sovereign cloud initiatives are specifically designed to meet these requirements, offering alternatives to global CDN providers for sensitive government infrastructure like the EUDI Wallet system.