Quantum Watermarking Research Articles

A Novel LSB Based Quantum Watermarking

Quantum watermarking is a technique which embeds the invisible quantum signal such as the owners identification into quantum multimedia data (such as audio, video and image) for copyright protection. In this paper, using a quantum representation of digital images a new quantum watermarking protocol including quantum image scrambling based on Least Significant Bit (LSB) is proposed. In this protocol, by using m-bit embedding key K 1 and m-bit extracting key K 2 a m-pixel gray scale image is watermarked in a m-pixel carrier image by the original owner of the carrier image. For validation of the presented scheme the peak-signal-to-noise ratio (PSNR) and histogram graphs of the images are analyzed.

Quantum Cosine Transform Based Watermarking Scheme for Quantum Images

A novel watermarking scheme for quantum image is proposed based on Quantum cosine transform (QCT). The cosine coefficients are extracted by executing QCT on quantum image. A dynamic vector for controlling embedding strength instead of a fixed parameter for embedding process in other scheme is utilized to process quantum watermark. The adder operation and the inverse QCT are implemented which offset the QCT and guarantee the embedding process having smaller impact on the quantum carrier image. Simulation results and analysis show that the proposed dynamic watermarking scheme has better visual quality under a higher embedding capacity.

A duple watermarking strategy for multi-channel quantum images

Utilizing a stockpile of efficient transformations consisting of channel of interest, channel swapping, and quantum Fourier transforms, a duple watermarking strategy on multi-channel quantum images is proposed. It embeds the watermark image both into the spatial domain and the frequency domain of the multi-channel quantum carrier image, while also providing a quantum measurement-based algorithm to generate an unknown key that is used to protect the color information, which accompanies another key that is mainly used to scramble the spatial content of the watermark image in order to further safeguard the copyright of the carrier image. Simulation-based experiments using a watermark logo and nine building images as watermark image and carrier images, respectively, offer a duple protection for the copyright of carrier images in terms of the visible quality of the watermarked images. The proposed stratagem advances available literature in the quantum watermarking research field and sets the stage for the applications aimed at quantum data protection.

A Quantum Watermarking Protocol Based on Bell Dual Basis

This paper presents a Bell-dual-basis-based quantum watermarking protocol composed of three major algorithms: watermark embedding and extracting and the intercepting test. The first two are completed by using the entanglement swapping property of Bell dual basis and the test is accomplished through IBF protocol to guarantee its bottom security. The watermarking protocol is mainly designed for the protection of digital copyright in the existence of classical information. This design finds that the quality of digital contents is not damaged with its zero-watermark attributes when embedding watermarks.

Analysis and improvement of the watermark strategy for quantum images based on quantum Fourier transform

We investigate the quantum watermark strategy for quantum images based on quantum Fourier transform proposed by Zhang et al.(Quantum Inf Process 12(2):793---803, 2013). It is aimed to embed the watermark image into the Fourier coefficients of the quantum carrier image without affecting the carrier image's visual effect. However, in our opinion the protocol is not clearly described and several steps are ambiguous. Moreover, we argue that the watermarking algorithm claimed by the authors is incorrect. At last, a possible improvement strategy is presented.

A Quantum Watermark Protocol

Quantum watermarking is the technique which embeds the invisible quantum signal such as the owner’s identification into quantum multimedia data (such as audio, video and image) for copyright protection. In this paper, a watermark strategy for quantum images is proposed based on flexible representation for quantum images (FRQI). Compared with the former strategy, which can only be used to verify the identity of the true owner of a carrier image, the proposed method can be used to find out who is the real owner, and our strategy’s capacity reaches the largest. It is impossible for anyone except the copyrighter to clear off or extract the watermark images.

Quantum Watermarking Using Entanglement Swapping

Digital watermarking is the process of embedding information into a digital signal in a way that is difficult to remove. In this article a secure quantum watermarking using entanglement swapping is proposed. Here the entanglement swapping is employed to build up a hidden layer of secure message under the conventional first layer of secure information sequence. In this protocol by insuring the security of transmission of the first layer of information sequence the security of the hidden secret messages is also proved to be reliable regardless of whether the hidden channel has been detected or not.

Watermarking and authentication of quantum images based on restricted geometric transformations

A secure, keyless, and blind watermarking and authentication strategy for images on quantum computers, WaQI, is proposed based on restricted geometric transformations. In contrast with conventional digital watermarking techniques where geometric transformations on the contents of an image are considered undesirable, the proposed WaQI scheme utilises the restricted variants (of the quantum versions) of these transformations as the main resources of the watermark embedding and authentication circuits. This is accomplished by a careful analysis of the classical content of the image–watermark pair, based on which a bespoke watermark map that translates into the gate sequences of the quantum watermark embedding and authentication circuits is realised. Simulation-based experimental results involving the classical (i.e. conventional or non-quantum) simulation of the input images, watermark signals, and quantum circuits yielded a 25% improvement in terms of overall watermark-embedding capacity and between 7% and 50.7% in terms of the visible quality of the watermarked images in comparison with select digital watermarking methods for various pairs, thus, demonstrating both the feasibility and capabilities of the proposed WaQI scheme when the necessary quantum hardware are realised physically. This scheme, provides the framework for representing two or more quantum data as a single quantum circuit, and opens the door for other applications aimed at quantum data protection.