Authorized NFC reading
The CAN helps establish a secure channel with the card. The data PIN authorizes access to available information. Codes are used in the current session and are not synced to iCloud.
Signing on the card
The cryptographic operation is authorized with the signing PIN and executed with the private key inside the eID. The app receives the signing result, never the private key.
Timestamp and PAdES-LT
For newly signed documents, the app requests a trusted timestamp and can archive certificate chains and OCSP/CRL evidence inside the PDF so long-term validation has the required information.
Online validation
When embedded evidence is insufficient or needs refreshing, the app may contact revocation addresses referenced by certificates. Network access is required for a complete conclusion about current status.
Library and iCloud
The library is local by default. If iCloud is enabled, eligible PDFs and metadata are stored in your private CloudKit database. NFC session data and access codes are excluded.
What you can do
Keep iOS updated, use the correct codes, review every document before signing, protect access to your iPhone, and share PDFs only with the intended recipients.