Protecting Hidden Transmission of Biometrics Using Authentication Watermarking

Compared with traditional personal identification techniques such as passwords and PIN codes, automated biometrics authentication provides a convenient and reliable method in diverse applications, but their validity must be guaranteed. Watermarking technique may be a solution to ensure the validity of biometrics. In this paper, a novel scheme of protecting hidden transmission of biometrics using authentication watermarking is proposed. Five watermark bits generated from each DCT block are split into two parts: authentication bits and hidden bits. The four authentication bits are utilized to verify the integrity of each image block; the hidden bit is used as a hidden channel to transmit the biometrics data. At the receiver, the integrity of each block is verified using authentication watermarking. The biometrics data is extracted from the block which has been marked as innocent. Redundancy embedding and voting scheme are used as enhancing the rightness of extracted biometrics data. Theoretical analysis and experimental results show that the proposed scheme protects hidden transmission of biometrics and can efficiently recover the biometrics when the watermarked-images suffer from malicious tamper.