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Neural Computing Research Group

Public Key Cryptography - A Statistical Mechanics Approach

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Introduction

Public Key Cryptography - A Statistical Mechanics Approach

An EPSRC funded project. This project is led by David Saad working with Nikos Skantzos . Jort van Mourik and Stephane Bounkong also contributed to some of the research activities.The research aims at studying analytically and numerically  a new matrix-based cryptosystem.  Insight gained from the analysis is being used to devise improved constructions that will be efficient, secure and practical.

Research Funding

EPSRC: 110,889 GBP

Duration

The project started in the February, 2001 and ended in 2003.


Project Background

The ever-increasing volume of sensitive data being transferred over the internet requires the use of advanced public-key cryptosystems, authentication methods and electronic signatures.  Some of the leading methods suffer from long decryption times, which indirectly reduce the cryptosystem's security level.The new cryptosystem is based on insight gained from the analysis of low-density parity-check codes, using methods of statistical physics.  The ciphertext is generated from modulo 2 sums of plaintext bits.  These are selected by employing two predetermined randomly constructed sparse matrices and a single dense matrix.  The generated ciphertext is then corrupted by random flip noise of given probability.  This probability, and the choice of plaintext bits to be added, constitute the public key;  the detailed knowledge of the matrices used constitute the private key.  Decryption is carried out using methods of belief-propagation, which are computationally economical.

Objectives

Applet

This applet was prepared with the help of Christian Rechberger

Further Information

We attempt to produce online versions of all relevant publications arising from this project. You can see a list of all the available technical reports by following the link below:

Online Publications

For additional papers in the areas of steganography and broadcasting please search the NCRG archive http://www.ncrg.aston.ac.uk/Papers/index.html

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