Optional multi-biometric cryptosystem based on fuzzy extractor

Following the wide use of smart devices, biometric cryptosystem is used to protect users´ privacy data. However, biometric cryptosystem is rarely used in the scenario of mobile cloud, because the biometric sensors are different on various devices. In this paper, an optional multi-biometric cryptosystem based on fuzzy extractor and secret share technology is proposed. Each of the enrolled biometric modality generates a feature vector, and then the feature vector is put into a fuzzy extractor to get a stable codeword, namely a bit-string. All the codewords are used to bind a random key based on a secret share method, and the key can be used to encrypt users´ privacy data. During the verification phase, part of the enrolled biometric modalities are enough to recover the random key. Therefore, the proposed scheme can provide a user the same biometric key on different devices. In addition, experiment on a virtual multi-biometric database shows that the novel concept of optional multi-biometric cryptosystem is better than the corresponding uni-biometric cryptosystem both in matching accuracy and key entropy.