Secure online image trading scheme using DCT coefficients and moment invariants feature

In this paper, we introduce a scheme that enables secure image trading over the Internet. The involved parties in our image trading system are image provider, server provider, and commercial user. The proposed scheme facilitates secure storing and retrieval of original images for trading, but prevents access to unauthorized users and untrustworthy server provider. The original images are visually protected in Discrete Cosine Transform (DCT) domain, and stored at a server. Thumbnails of original images are generated and publicly accessible. A commercial user will browse these thumbnails which also serve as queries. Image matching between thumbnails and protected images is accomplished utilizing the DC component of DCT coefficients and moment invariant feature. Simulation results confirmed the effectiveness of the proposed method.