Biometric yet privacy protecting person authentication

Abstract

Many eligibility or entitlement certificates in every day life are non-transferable between persons. However, they are usually implemented by personal physical tokens that owners can easily pass around (e.g. credit card), driver’s license). So there must either be negligible incentives to pass these certificates or the tokens around, or the tokens must allow to authenticate the persons who show certificates, e.g., by imprinted photographs. However, any kind of easily accessible personal identifying information threatens the owners’ privacy. To solve these somehow paradoxical requirements, we assume for each owner a kind of pilot that is equipped with a tamper resistant biometric authentication facility. We draft cryptographic protocols for issuing and showing non-transferable yet privacy protecting certificates. Unforgeability of certificates relies on a well-established computational assumption, nontransferability relies upon a physical assumption and owners’ privacy is protected unconditionally.