Bit priority-based biometric watermarking

In remote biometric authentication systems, raw biometric data stored in centralized databases or being transferred in communication channels are normally encrypted for security purposes. However, encryption does not provide security once the data are decrypted. Biometric watermarking can overcome this problem. The decrypted biometric data are still embedded in an image container and are only retrieved if a secret key is provided. It has been observed that retrieval error is very high if the embedded biometric data are numeric. We proposed a new method based on amplitude modulation and bit priority to embed high priority bits at good positions to reduce the retrieval error when they are converted to numeric data. Experimental results show a significant error reduction for the proposed method.