Flexible authentication of images

In this paper, we propose a novel authentication method for digital images that achieves fine authenticating granularity (e.g., block-level granularity). Its appealing flexibility lies in the fact that with only one piece of authenticating data (e.g., digital signature or message authentication code) spanning all blocks, each block can be independently authenticated while ignoring the other blocks. In our method, the authenticating data are derived by means of the Chinese Remainder Theorem. To further attest its flexibility, the method provides adjustable confidence by managing the public system parameters. Security issues, advantages, as well as limitations related to the method are addressed. A wide range of potential applications are envisioned to demonstrate its practical significance.