An alignment-free fingerprint cryptosystem based on fuzzy vault scheme

Fuzzy vault is a practical and promising scheme, which can protect biometric templates and perform secure key management simultaneously. Alignment of the template biometric sample and the query one in the encrypted domain remains a challenging task. While implementing fuzzy fingerprint vault, the accuracy of alignment in encrypted domain cannot be ensured and the information leakage may be caused because of the alignment. In this paper, an alignment-free fingerprint cryptosystem based on fuzzy vault scheme is developed fusing the local features, known minutia descriptor and minutia local structure, which are invariant to the transformation in fingerprint capturing. Three fusion strategies are employed to integrate the two local features. Huffman coding technology is used to compress the storage volume of the minutia descriptor vault. The proposed fingerprint cryptosystem can avoid the alignment procedure and improve the performance and security of the fuzzy vault scheme at the same time. Experiments on FVC2002-DB2a and FVC2002-DB1a are conducted to show the promising performance of the proposed fingerprint cryptosystem. Security level of proposed cryptosystem will not decrease and even rise in some circumstances. The best trade-off results obtained is GAR1⁄4 92% ðFAR1⁄4 0Þ, under the 53-bit security. Despite the larger template storage expense, the proposed alignment-free fingerprint cryptosystem outperforms the minutiae-based fingerprint cryptosystems with alignment in the terms of accuracy and security. & 2009 Elsevier Ltd. All rights reserved.