The cryptography behind electronic passports
6 months ago
- #electronic-passports
- #security
- #cryptography
- Electronic passports (eMRTDs) contain embedded filesystems with personal data and cryptographic protocols.
- ICAO standards define the structure and security of electronic passports, including mandatory and optional data groups (DGs).
- Threat model includes preventing unauthorized reading, eavesdropping, forgery, and copying of passport data.
- Basic Access Control (BAC) uses MRZ data for key derivation but has security flaws like low entropy and offline brute-force vulnerability.
- Passive Authentication (PA) verifies passport data integrity via signatures from Country Signing Certificate Authority (CSCA).
- Active Authentication (AA) prevents copying by using a private key stored in the passport, but has relay attack vulnerabilities.
- Extended Access Control (EAC) improves security with Chip Authentication (CA) and Terminal Authentication (TA).
- Password Authenticated Connection Establishment (PACE) replaces BAC, using MRZ data more securely to prevent offline attacks.
- Threat model gaps include potential tracking if MRZ data is exposed and fingerprinting based on passport characteristics.
- Zero-knowledge identity proofs with passports raise security concerns, including data exposure and reliance on PA/AA/CA.