Externalized Fingerprint Matching

Abstract

This paper describes a very inexpensive memory card (phonecard-like card) capable of performing fingerprint matching. In the proposed protocol the card stores the user’s fingerprint information to which random minutiae were added at enrolment time (we denote this scrambled template by t). The card also stores a binary string w encoding which of the minutiae in t actually belong to the holder. When an identification session starts, the terminal reads t from the card and, based upon the incoming scanner data, determines which of the minutiae in t are genuine. The terminal forms a candidate w′ and sends it to the card. All the card needs to do is test that the Hamming weight of w ⊕ w′ is smaller than a security threshold d. It follows that the card only needs to embark passive data storage capabilities, one exclusive-or gate, a shift register, a counter and a comparator (less than 40 logical gates).