Private Passport Matching

Match passport attributes across parties without revealing the underlying document data. Built on the same MPC network TACEO co-architected for zkPassport.

The Problem

Passports are the standard identity document in the physical world, making them a natural anchor for digital identity systems as well. But operating on passport data digitally requires careful handling: the underlying attributes are sensitive, tied to a real person, and cannot be rotated if compromised.

A common mitigation is to hash the passport data before any comparison, so the raw document is never transmitted. This limits casual observers - but not the issuers. Passport-issuing authorities might hold the original data and can compute the same hashes, making users traceable to any party that issued their document.

The Solution

TACEO:OPRF computes a nullifier over the passport hash using a threshold of independent MPC nodes. The resulting nullifier is deterministic - it uniquely identifies the user - but no single party, including TACEO or the document issuer, can compute it unilaterally. Knowledge of the passport's pre-image is no longer sufficient to derive or link the identifier.