Guihua Zeng

Arbitrated quantum-signature scheme

The general principle for a quantum-signature scheme is proposed and investigated based on ideas from classical signature schemes and quantum cryptography. The suggested algorithm is implemented by a symmetrical quantum key cryptosystem and Greenberger-Horne-Zeilinger (GHZ) triplet states and relies on the availability of an arbitrator. We can guarantee the unconditional security of the algorithm, mostly due to the correlation of the GHZ triplet states and the use of quantum one-time pads.

Seeded region growing: an extensive and comparative study

Seeded region growing (SRG) algorithm is very attractive for semantic image segmentation by involving high-level knowledge of image components in the seed selection procedure. However, the SRG algorithm also suffers from the problems of pixel sorting orders for labeling and automatic seed selection. An obvious way to improve the SRG algorithm is to provide more effective pixel labeling technique and automate the process of seed selection. To provide such a framework, we design an automatic SRG algorithm, along with a boundary-oriented parallel pixel labeling technique and an automatic seed selection method. Moreover, a seed tracking algorithm is proposed for automatic moving object extraction. The region seeds, which are located inside the temporal change mask, are selected for generating the regions of moving objects. Experimental evaluation shows good performances of our technique on a relatively large variety of images without the need of adjusting parameters.

Joint remote state preparation of arbitrary two- and three-qubit states

We present a scheme for joint remote preparation of an arbitrary two-qubit pure state in a probabilistic manner from a spatially separated multi-sender to one receiver; the scheme is then extended to the arbitrary three-qubit case. We show that by adding some classical communication and local operations, the success probability of preparation can be increased to four times for two-qubit states and eight times for three-qubit states, and can reach one under certain conditions.

Long-distance continuous-variable quantum key distribution by controlling excess noise.

Quantum cryptography founded on the laws of physics could revolutionize the way in which communication information is protected. Significant progresses in long-distance quantum key distribution based on discrete variables have led to the secure quantum communication in real-world conditions being available. However, the alternative approach implemented with continuous variables has not yet reached the secure distance beyond 100 km. Here, we overcome the previous range limitation by controlling system excess noise and report such a long distance continuous-variable quantum key distribution experiment. Our result paves the road to the large-scale secure quantum communication with continuous variables and serves as a stepping stone in the quest for quantum network.

A Generalized Reverse Block Jacket Transform

Jacket matrices motivated by the center weight Hadamard matrices have played important roles in signal processing, communication, image compression, cryptography, etc. In this paper we propose a notation called block Jacket matrix which substitutes elements of the matrix into common matrices or even block matrices. Employing the well-known Pauli matrices which are very important in many subjects, block Jacket matrices with any size are investigated in detail, and some recursive relations for fast construction of the block Jacket matrices are obtained. Based on the general recursive relations, several special block Jacket matrices are constructed. To decompose high order block Jacket matrices, a fast decomposition algorithm for the factorable block Jacket matrices is suggested. After that some properties of the block Jacket matrices are investigated. Finally, several remarks are presented. These remarks are associated with comparisons between the Clifford algebra and the block Jacket matrices, generations of orthogonal and quasi-orthogonal sequences, and relations of the block Jacket matrices to the orthogonal transforms for signal processing. Since the Pauli matrices are actually infinitesimal generators of SU(2) group, the proposed construction and decomposition algorithms for the block Jacket matrices are available in the signal processing, communication, quantum signal processing and information theory.

CONTINUOUS VARIABLE QUANTUM SIGNATURE ALGORITHM

A true quantum signature algorithm based on continuous-variable entanglement state is proposed. In the suggested algorithm, a key-pair, i.e. private signature key and public verification key, is generated based on a one-way function. By employing the signature key, a message state is encoded into a 2k-particle entangled state and a two-particle entangled state is prepared. The resulting states are exploited as a signature of the message state. The signature can be decoded under the verification key when it needs to be verified. Subsequently, a decoded message state and a two-particle entangled state are obtained. To compare the decoded states and the original states, a quantum circuit for comparing these states is exploited. Making use of measurement results of the quantum circuit one can judge the authenticity of the received signature. According to the security requirement of the signature scheme, the suggested algorithm has been proven to be theoretically secure by using the Shannon information theory.

Continuous-variable quantum key distribution with 1 Mbps secure key rate.

We report the first continuous-variable quantum key distribution (CVQKD) experiment to enable the creation of 1 Mbps secure key rate over 25 km standard telecom fiber in a coarse wavelength division multiplexers (CWDM) environment. The result is achieved with two major technological advances: the use of a 1 GHz shot-noise-limited homodyne detector and the implementation of a 50 MHz clock system. The excess noise due to noise photons from local oscillator and classical data channels in CWDM is controlled effectively. We note that the experimental verification of high-bit-rate CVQKD in the multiplexing environment is a significant step closer toward large-scale deployment in fiber networks.

Human action detection via boosted local motion histograms

This paper presents a novel learning method for human action detection in video sequences. The detecting problem is not limited in controlled settings like stationary background or invariant illumination, but studied in real scenarios. Spatio-temporal volume analysis for actions is adopted to solve the problem. To develop effective representation while remaining resistant to background motions, only motion information is exploited to define suitable descriptors for action volumes. On the other hand, action models are learned by using boosting techniques to select discriminative features for efficient classification. This paper also shows how the proposed method enables learning efficient action detectors, and validates them on publicly available datasets.

Fast Cocyclic Jacket Transform

This correspondence presents a fast cocyclic Jacket transform over the complex number field. With the aid of the Kronecker product, the successively lower order cocyclic Jacket matrices and identity matrices, fast algorithms for realizing the one and two dimensional cocyclic Jacket transform are proposed. It can be applied in signal processing, quantum Information, cryptography, orthogonal code design, and information theory.

Quantum Private Communication

Quantum Private Communication covers the fundamentals of the areas of secure communication, quantum cryptography, quantum communication, and their physical implementation with applications. The book appears in a timely manner for an emerging field at the crossroad of classic private communication and quantum physics. Graduate students and scientists alike in communication engineering, computer science, electronic engineering, physics and mathematics will benefit from the book. Professor Guihua Zeng teaches and conducts research at the Department of Electronic Engineering of Shanghai Jiao Tong University and spent an Alexander von Humboldt Fellowship at the University of Freiburg, Germany.