Abstract: Data from biometric images such as minutiae of a fingerprint are represented in coordinates x- and y-, and the direction of the ridge flow of the minutia ?; in vector sets of (x1, y1, ?1) are used in generating a 256-bit secret key in a secure manner in enrolling the fingerprint in the Enrolment Phase. The key generation algorithm includes random key generation, threshold signature scheme using polynomial functions, generating random fake minutiae vector sets to form a locked representation of the fingerprint. In the Query Phase, the fingerprint image used to re-generate the secret key is matched against the locked template representation through automatic alignment process using geometric hash table to compare the enrolled minutiae (genuine and fake) with the vector set extracted from the query minutiae sets, and adjustable transform equation is used for adjusting for the minutiae direction, etc.