Siren: Secure Data Sharing Over P2P and F2F Networks

In this paper we propose a decentralized privacy-preserving system which is able to share sensible data in a way, that only predefined subsets of authorized entities can recover the data; either after getting an alarm message or timing out. The protocol has two main communication channels: a P2P network where the encrypted information is stored, and a smaller private P2P network, which consists of the authorized parties and is called a friend-to-friend network. We describe the communication protocols fulfilling the desired security requirements and present some results on the implementation of the system. The main cryptographic building blocks of the protocol include symmetric cryptographic primitives and a t-threshold secret sharing scheme.

Pseudo-Zernike Moments for Feature Extraction and Chinese Character Recognition

In this paper I present a pseudo-Zernike feature descriptor based recognition technique for accurate identification of printed and handwritten Chinese characters. Chinese character recognition is a hard topic amongst other character recognition problems not only because the sheer number of different characters to identify, but also because of the characters’ dense and complex nature. Moment functions have been successfully applied to many shape recognition problems, due to the fact that they tend to capture global features, which makes them well suited as feature descriptors. However simple moment based techniques fail at capturing the different features of structurally complex objects, such as Chinese characters. To solve this problem more efficient moment functions have to be used. (draft) (LaTeX source)

Detection of visual actions in a chess game using image processing (Hungarian)

My BSc thesis. The work covers the detection of each move in a chess game played by human opponents, while analyzing the different states of the game and projecting useful information back to the user.

Calculating Channel Capacity with the Arimoto-Blahut Algorithm (Hungarian)

A brief paper describing the Arimoto-Blahut algorithm for calculating channel capacity matrices. (LaTeX source)

Reed-Solomon codes (Hungarian)

A brief introduction to RS codes and finite fields. An RS encoder/decoder is available in the projects section, though it is very slow and useful only for educational purposes. (LaTeX source)

An Axiomatic World (Hungarian)

An essay on the clash, between the views of physicalist and mathematical philosphy. This paper was written for a philosophy class. (LaTeX source)