A Secure and Trustworthy Digital Passport System Using Self-Sovereign Identity and Blockchain
Document fraud, particularly involving passports, poses significant security risks and can lead to severe consequences such as unauthorized entries into a country. Blockchain technology has advanced the concept of Self-Sovereign Identity (SSI), a user-controlled and secure identity management paradigm built on top of blockchain technology. This paper proposes a two-layer blockchain-based SSI digital passport system. The first layer establishes a trusted consortium of countries that serves as a decentralized trust anchor, enabling governance, interoperability, and secure cross-border collaboration analogous to existing international passport verification frameworks. The second layer builds on this foundation to implement an SSIbased digital passport using Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs), allowing users to carry and verify their passports digitally while maintaining privacy through selective disclosure. We present the architecture and detailed protocol of the proposed system, analyze security and privacy threats, and describe how these threats mitigated through concrete design requirements. Finally, a Proof-of-Concept (PoC) implementation using state-of-the-art technologies demonstrates the system's feasibility and evaluates its performance.