Chaotic Cryptosystems  
 

Professor Alaa Fahmy
University Of Calgary,
Electrical & Computer Engineering Dept.,
Canada
E-mail: af200345@hotmail.com
 

Abstract: One-dimensional chaotic maps have been used to construct private-key block/stream cryptosystem with or without error propagation property. The constructed cryptosystem is based on the main features of one-dimensional chaotic maps, mainly the sensitive dependence on initial conditions and the unpredictability of chaos. The ciphertext is obtained by iterating the inverse map with an initial condition, which represents the plaintext. The number of iterations N are determined by the plaintext's accuracy digits p, i.e.,. N=p/log102 iterations. At that point, all information about the initial condition is lost.

A proposed private-key stream cryptosystem, based on logistic map, has been introduced. Moreover, two-dimensional chaotic map has been used for compression as well as encryption. Various techniques for the construction of the Message Authentication Code (MAC) have been presented. The methods for resolving the problem of disputes have been discussed. A new signature scheme, based on chaotic map, has been presented. This signature scheme allows any receiver to recognise the sender's signature but not to forge it. The signature cannot be verified without cooperation of the signer.