The International Civil Aviation Organization (ICAO) has specified VDS-NC as its standard for cross-border digital health certificates, including COVID-19 vaccination and testing certificates. VDS-NC stands for Visible Digital Seal for Non-Constrained Environments. VDS-NC certificates: - leverage the ePassport public key infrastructure (PKI) that ICAO member states around the world have been using since 2004 - are like a passport chip in QR format, with the same high level of security against f