Abstract: By merging several kinds of user authentication information such as fingerprints, faces, passwords etc., multi-modal authentication can improve the security of traditional identify authentication systems. Furthermore, via data hiding technology, specific user identities can be imbedded into their biologic templates to ensure safe storage. A multi-modal authentication scheme was introduced, which uses fingerprint templates as the cover. The key problem of this technology is to ensure the quality of the template picture after embedding, which is important for the matching precision afterwards. Both theoretical analysis and experimental results demonstrate that by adopting a coding method which increases the sparseness of the original binary data before embedding, modification of the fingerprint template is lowers effectively, thus ensuring the image quality and matching precision. The method embeds fragile watermarks for the integrity authentication of the fingerprint template.

Key words: fingerprint template, data hiding, lossless data hiding, reverse zero run length (RZL) coding