ICAO Public Key Directory and chip authentication secure electronic passports

The International Civil Aviation Organization (ICAO) utilizes the Public Key Directory (PKD) to facilitate the international exchange of cryptographic certificate information. This infrastructure allows border authorities to authenticate electronic travel documents by verifying the electronic signatures created by foreign passport issuers.

While countries could theoretically use bilateral arrangements to exchange certificates, the PKD provides a centralized platform to manage the complexity of hundreds of individual relationships, periodic certificate replacements, and revocation information.

Complementing this, Chip Authentication provides an additional layer of security by verifying the authenticity of the physical contactless chip itself. While Passive Authentication ensures that identity information remains unchanged, Chip Authentication uses an interactive cryptographic process to ensure that the data is being presented by a legitimate, original integrated circuit rather than a digital copy.