A novel biometrie key scheme

Because most cryptosystems adopt standard encryption algorithms, the security of a cryptosystem depends on the security of the cryptographic key. As a pseudorandom number of fix-length, there is no connection between a key and its valid user. No matter how long the key is, the whole system falls apart completely if the key is stolen or shared with an illegitimate user by a conspirator, which is a serious security trouble that many cryptosystems are facing. Since current biometric recognition techniques cannot produce biometric information consistent enough to be used as a key directly, Biometric key scheme (BKS) can solve the problem by binding a biometric template and a cryptographic key monolithically. BKS is devised in such a way that the cryptographic key can be retrieved precisely if and only if a matching biometric template is available. A novel biometric key scheme based on modular secret sharing is proposed in this paper. The feasibility and high security have been proved by theoretical analysis and experiments. In the experiment of combining iris recognition with the scheme, the probability of an illegitimate user to retrieve a cryptographic key is zero; the probability of a legitimate user fail to retrieve a cryptographic key is 0.0571. It is 2⁶⁴⁵ times more difficult for an attacker to retrieve the cryptographic key comparing to a legitimate user.