Privacy and Security Enhancements in Biometrics

Many tout biometrics as the key to reducing identify theft and providing significantly improved security. However, unlike passwords, if the database or biometric is ever compromised, the biometric data cannot be changed or revoked. We introduce the concept of Biotopes^TM, revocable tokens that protect the privacy of the original user, provide for many simultaneous variations that cannot be linked, and that provide for revocation if compromised. Biotopes can be computed from almost any biometric signature that is a collection of multibit numeric fields. The approach transforms the original biometric signature into an alternative revocable form (the Biotope) that protects privacy while it supports a robust distance metric necessary for approximate matching. Biotopes provide cryptographic security of the identity; support approximate matching in encoded form; cannot be linked across different databases; and are revocable. The most private form of a Biotope can be used to verify identity, but cannot be used for search.We demonstrate Biotopes derived from different face-based recognition algorithms as well as a fingerprint-based Biotope and show that Biotopes improve performance, often significantly!

The robust “distance metric”, computed on the encoded form, is provably identical to application of the same robust metric on the original biometric signature for matching subjects and never smaller for nonmatching subjects. The technique provides cryptographic security of the identity, supports matching in encoded form, cannot be linked across different databases, and is revocable.