Digital Watermarking And Identity Authentication Based On Secret Sharing

The secure protection of secret image is an important research area ofinformation security. Image secret sharing (ISS) mainly resolves the problems oflosing and modifying of the secret image information in storage and transmission, andimproves the security of the secret image’s protection. Currently, the research ofimage secret sharing techniques can be divided into two categories: visualcryptography sharing (VCS) and polynomial-based ISS (PISS). VCS is suitable forthe situation where no computation resources are available, and the perfect revealingof the secret image is not required. PISS needs computer to reveal the perfect secretimage. This dissertation mainly addresses the researches of ISS methods byimproving efficiency and visual quality. It first proposed a secure imagewatermarking algorithm using the visual cryptography (VC). Then A quantumprotocol for (t,n)-threshold identity authentication based onGreenberger-Horne-Zeilinger states and PISS is presented. All research contents areas follows.（1）ptography and frequency domain transformation. We use the visual secretsharing technology to construct two shares. Features of the original image areextracted using decomposition, and are used to generate the master share. Ownershipshare is generated with the help of secret image (watermark) and the master share,using VCS technique. The master shares and ownership shares can be stackedtogether to give the copyright image verifying the ownership about the host image.（2）A quantum protocol for (t,n)-threshold identity authentication based onGreenberger-Horne-Zeilinger states is presented. A trusted third party (TTP) canauthenticate the users at the same time and only when t or more users among n applyfor authentication. Compared with the previous multiparty simultaneous quantumidentity authentication (MSQIA) protocols, the proposed scheme is more flexible andsuitable for practical applications.