Ye Yun

A new steganography method via combination in PowerPoint files

Steganography is the science of communicating secret information which no one apart from the intended recipient can be aware of. Most researchers focus on the medium of image, video and audio, while text is paid less attention, especially PowerPoint documents due to some shortcomings. In this paper, a new steganography method which hides information via different combinations of different objects in a PowerPoint file is proposed. Combination is widely used in PowerPoint files to help people operate different objects simultaneously. During our hiding process, the original content of the PowerPoint file is not changed at all, thus making the result stegodocument more natural and safe from traditional attacks compared to other steganography method.

Efficient Secure Protocols to Determine Whether a Point is inside a Convex Hull

Secure Multi-party Computation (SMC) is dedicated to solve trust problems in cooperative computing with each participant’s private data. Privacy Preserving Computational Geometry (PPCG) is a special area in SMC and is being widely used. This paper investigates the problem of judging whether a point is in a convex hull or not. We firstly present a secure protocol to determine the position of a private point and a private line, based on which two efficient point-inclusion schemes are proposed. Compared with previous solutions, our protocols perform better in efficiency, especially when the number of the convex hull’s points is large.

A Secure Protocol for Determining the Meeting Points of Two Intersected Circles

Secure Multi-party Computation (SMC) deals with the problem of secure computation among participants who are not trusted by others. Privacy Preserving Computational Geometry is a special area in SMC and has been applied to various of areas such as military, commerce and governments et al. In this paper, we will propose an efficient secure protocol, which is based on numerical computation, for the problem of determining the meeting points of two intersected circles, which is a practical problem in our daily life. In our solution, the communicational complexity can be lowered to just Ο(12*(logR1+ logr2)), where R1 and R2 are the radius of the two circles respectively. We also present the experimental results in this paper.