Bai Sen

An Image Encryption Algorithm Based on Knight's Tour and Slip Encryption-Filter

A new image encryption algorithm is proposed in the paper. Its essential idea is that, firstly, we produce a knights tour matrix emended as slip encryption-filter template matrix; And then, we produce a knights tour matrix again with the same size of the image waiting for encryption as a knights tour slip matrix; Finally, we let the center of the slip encryption-filter template move along with the knights tour slip matrix to do convolvsion operation, and achieve the cipher image. Experimental results show that the algorithm has perfert encryption effect, high encryption efficiency, simplity to achieve, huge secret key space and high security.

An Ant Colony Optimization Algorithm for Knight's Tour Problem on the Chessboard with Holes

Knight’s tour problem (KTP) on the chessboard with holes is an especial but interest tour problem. We improve the basic ant colony optimization,and introduce more better pheromone resource update and sharing mechanism,, and find its tour path solutions on the chessboard with holes with the help of colonies sharing the information resource by their intercommunion. We have used the algorithm to encumerate the knight’s tours on different chessboard with holes, and made the particular analysis for produce. Experiment results show that the algorithm not only produce the path solutions quickly on the chessboard with holes, but also is easy to control the path starting square and path style.

Robust Information Hiding in Speech Signal Based on Pitch Period Prediction

The paper managed to propose a robust information hiding method in speech signal with respect to low bit rate codecs. A novel pitch period prediction method of speech signal for information hiding is presented. It first estimates the pitch period of short time speech signal, and then predicts the next period data by the previous one with one parameter according to the least-mean-square-error criterion. Based on the basic idea of Scalar Costar Scheme (SCS), the secret information is embedded into the predict parameter and thus generates the stego speech. Experiments indicate that the stego speech is imperceptive to human ears, and it can resist to attacks such as additive noise, resampling, especially to speech codecs employed in GSM and CDMA.

Image encryption and compression based on the generalized knight's tour, discrete cosine transform and chaotic maps

An efficient and simple encryption and compression scheme for digital image is reported in this paper. This scheme is based on the algorithm of the generalized knight’s tour, discrete cosine transform and non-linear chaotic maps. In this scheme, according to the structure of compression, confusion and diffusion are attained by methods of the generalized knight’s tour and chaotic maps. Firstly, the generalized knight’s tour algorithm is utilized to scramble the pixels while the data correlation preserved. Then, the chaotic system is used to generate a pseudorandom permutation to encrypt the part of coefficients from discrete cosine transform for diffusion. Experimental results show that the proposed scheme can gain robust security and a high compression ratio, which indicates that the proposed scheme is practicable.

Implementation of Steganography Based on HOOK

So far the steganography based on streaming media is widely studied,but rarely of it is based on instant communication tools. This paper improved the previous steganography which was implemented by HOOK based on instant communication tool. The improved methods contain adaptive sockets functions hooking(ASFH) and speech recognition based on socket functions,which can be generally applied in the instant communication tools,at last we implemented these methods in the covert channels of Bol SipPhone and Gtalk. Experimental results presents that the methods are actually feasible in the communication process. Which broaden the scope of steganography based on the streaming media and have a good realistic significance.

Beacon design for GPS-Free wireless sensor networks

A beacon for ranging in GPS-Free sensor networks is described, Combining the advantages of both narrowband and high distance estimation accuracy. The system uses the same frequency band for both communication and ranging purposes so that no separate dedicated ranging transceiver is needed. The special designed waveform of the signal is introduced, and the algorithms in the receiver module, especially the TOA estimation method, are described in detail. Simulation results show that the proposed beacon performs well under interference of AWGN.

An Efficient Algorithm for the Generalized (1,k)-Knight's Tours Problem

Knight’s tours are a fascinating subject. In[Discrete Appl. Math 150 (2005) 80-98],G.L.Chia and Siew-Hui Ong have presented generalized knight’s tours problem for the first time. In this paper, (i) we research the least chessboard(defined in Section 2) of (a,b)-knight’s tours (Section 3).(ii) we present an algorithm to (1,k)-knight’s tours which runs in O(nm) (Section 4).