Reversible watermarking technique to enhance security of a biometric authentication system

For every biometric template protecting technique, non-reversibility, accuracy, and revocability are essential features. Several template protecting techniques like bio-hash or biometric crypto system are used to transform raw biometric features into alternative form known as protected template [2]. As the protected templates are non-reversible, biometric verification is done in a transform domain. Tampered or stolen protected template may cause false validation; therefore its authentication in the database is essential. Reversible watermarking technique provides one such effective mechanism. Watermark protected templates are stored in the database at the time of its enrollment. During verification phase, incoming query template is compared with many database templates until a match is established. This verification technique increase complexity and burden on a biometric authentication system. In this paper, we propose a tag based template searching in reversible watermarking technique to check authenticity and reduce burden on biometric authentication system. In the proposal, rotation, scale and translation (RST) invariant features of biometric image are used for tagging the data. Watermark reversibility in the proposed method ensures that its presence do not affect native biometric authentication. Moreover presence of watermark in the biometric template provides security against replay attack.