Developing an Original Privacy-Preserving Biometric Authentication Protocol for Nigerian National Identity Systems

Nigeria's national biometric identity infrastructure stores and processes highly sensitive biometric data of over 100 million enrolled citizens, and the current centralised storage architecture creates catastrophic privacy risks from data breaches or state misuse, motivating the development of cryptographically strong privacy-preserving authentication protocols that eliminate the need to store raw biometric templates. This study developed an original privacy-preserving biometric authentication protocol specifically designed for the Nigerian national identity system architecture, making three original cryptographic and system design contributions. First, an original fuzzy commitment scheme based on error-correcting codes was designed for fingerprint template protection, tolerating up to 18 percent fingerprint minutiae variation while achieving false acceptance rate of 0.004 percent and false rejection rate of 1.8 percent in experiments on the FVC2002 fingerprint benchmark, validated against Nigerian-origin fingerprint patterns from the NIMC enrolment database under a research agreement. Second, a secure multi-party computation protocol was designed allowing distributed matching across three NIMC data centres without any single centre holding a complete biometric record, using secret sharing with 3-of-3 threshold reconstruction. Third, a zero-knowledge proof of identity protocol was developed enabling citizens to prove identity attributes (age bracket, citizenship) without revealing biometric data, implemented using the zk-SNARK Groth16 proof system. End-to-end authentication latency for the full privacy-preserving protocol was 2.1 seconds on reference server hardware, within the 3-second usability threshold. Expert review by 20 cryptography and biometric systems specialists confirmed the protocol's original contribution.

Keywords: privacy-preserving biometrics, fuzzy commitment, zero-knowledge proof, national identity, Nigeria