Out of several enrollment templates a vector of consistent bits (BioCode) and their positions are extracted.
When an enrollment biometric template is encrypted by p k i, this can solely be decrypted using the private key shares of the user (left (s{k_{i}^{1}}right)) and the verifier (left (s{k_{i}^{2}}right)) collaboratively since the proposed system is based on the (2,2 -threshold homomorphic cryptosystem.
For example, the Web site of the American College of Radiology Imaging Network provides access to standard enrollment form templates and sample protocols [ 33].
In enrollment stage, when selecting templates, the number of templates is set beforehand.
A increase of maximum key size is achieved in various scenarios, e.g., when applying several biometric templates at enrollment and authentication or when increasing the desired false rejection rates.
Physiological as well as behavioral biometric characteristics are acquired applying adequate sensors and distinctive features are extracted to form a biometric template in an enrollment process.
As the technology matures, users demand better performance against non-ideal (poor) biometric signals, e.g., border crossing systems should be able to capture the biometric signal of the iris or face while patrons are moving or computers should be able to authenticate patron credentials 10 years or more after enrollment without the requirement of template updating.
If an attacker is in possession of several different types of helper data and valid secret keys of the same user, a correlation of these can be utilized to reconstruct an approximation of biometric templates acquired at enrollment.
In the first stage, enrollment stage, we adopt an effective template selection method to select those fingerprints which best represent a finger, and then, a polyhedron is created by the matching results of multiple template fingerprints and a virtual centroid of the polyhedron is given.
In most cases, revoking keys require re-enrollment (original biometric templates are discarded after enrollment).
