Secret sharing is particularly important in the field of information security, which allows for the reconstruction of secret information from secure shares. However, due to the large amount of data and non-integer data type of 3D (three-dimensional) models, it is less efficient to perform sharing compared to the 2D(two-dimensional) digital images. In order to enable efficient sharing of 3D models as well, this article designs different circuit modules to parallelize the process of sharing 3D models. The proposed structure exploits the vertex extension to perform a complete reconstruction of the 3D model. In the sharing phase, the symmetric similarity of 3D model is exploited to realize the sharing in parallel, which improves the efficiency of sharing. In the reconstruction phase, the Strassen algorithm is used to optimize matrix multiplication, which saves circuit resources. Simulation results show that the structure performs more than 100 times faster than software. The utilization of circuit resources and the size of the share are both optimized. The validity of the designed hardware architecture is confirmed after analyzing the data from experiments performed on several 3D models.

Quantum teleportation faithfully transfers quantum bits (qubits) between distant nodes, which enables global quantum communication network. In this paper, a scheme for faithful multi-hop qubit transmission is proposed employing parallel quantum measurements. In terms of communication delay, the proposed scheme transports a qubit in time almost the same as the one-hop quantum teleportation does regardless of the number of hops between the source and destination.

In visual cryptography (VC) for grayscale image, size reduction leads to bad perceptual quality to the reconstructed secret image. To improve the quality, the current efforts are limited to the design of VC algorithm for binary image, and measuring the quality with metrics that are not directly related to how the human visual system (HVS) perceives halftone images. We propose an analysis-by-synthesis (AbS) framework to integrate the halftoning process and the VC encoding: the secret pixel/block is reconstructed from the shares in the encoder and the error between the reconstructed secret and the original secret images is fed back and compensated concurrently by the error diffusion process. In doing so, the error between the reconstructed secret and original secret is pushed to high frequency band, thus producing visually pleasing reconstructed secret image. This framework is simple and flexible in that it can be combined with many existing size-invariant VC algorithms, including probabilistic VC, random grid VC and vector/block VC. More importantly, it is proved that this AbS framework is as secure as the traditional VC algorithms. Experimental results demonstrate the effectiveness of the proposed AbS framework.

Spectrum shaping of watermark is necessary when the host signal is colored. This paper proposes a spectrum shaped dither modulation watermarking scheme. The covariance matrix of the watermark is scaled version of the host covariance matrix, so the corresponding spectrum of the watermark is proportional to the spectrum of the host signal. The performance of the proposed system is analyzed in terms of average probability of bit decoding error; closed form expression is derived. Theoretical analysis is finally validated by Monte Carlo simulation.

The security of the "autoregressive (AR) watermark in AR host" signal model is investigated. It is demonstrated through analysis and Monte Carlo simulation that the AR watermarking model is asymptotically as secure as the "white watermark in white host" model under the guessing attack