Biblio

This paper proposes a new hybrid technique for combined encryption text and image based on hyperchaos system. Since antiquity, man has continued looking for ways to send messages to his correspondents in order to communicate with them safely. It needed, through successive epochs, both physical and intellectual efforts in order to find an effective and appropriate communication technique. On another note, there is a behavior between the rigid regularity and randomness. This behavior is called chaos. In fact, it is a new field of investigation that is opened along with a new understanding of the frequently misunderstood long effects. The chaotic cryptography is thus born by inclusion of chaos in encryption algorithms. This article is in this particular context. Its objective is to create and implement an encryption algorithm based on a hyperchaotic system. This algorithm is composed of four methods: two for encrypting images and two for encrypting texts. The user chose the type of the input of the encryption (image or text) and as well as of the output. This new algorithm is considered a renovation in the science of cryptology, with the hybrid methods. This research opened a new features.

Multivariate public key cryptosystem acts as a signature system rather than encryption system due to the minus mode used in system. A multivariate encryption system with determinate equations in central map and chaotic shell protection for central map and affine map is proposed in this paper. The outputs of two-dimension chaotic system are discretized on a finite field to disturb the central map and affine map in multivariate cryptosystem. The determined equations meet the shortage of indeterminate equations in minus mode and make the general attack methods are out of tenable condition. The analysis shows the proposed multivariate symmetric encryption system based on chaotic shell is able to resist general attacks.

The importance of the task of countering the means of unauthorized access is to preserve the integrity of restricted access information circulating in computer networks determines the relevance of investigating perspective methods of cryptographic transformations, which are characterized by high speed and reliability of encryption. The methods of information security in the telecommunication system were researched based on integration of encryption processes and noise-immune coding. The method for data encryption based on generic polynomials of cyclic codes, gamut of the dynamic chaos sequence, and timer coding was proposed. The expediency of using timer coding for increasing the cryptographic strength of the encryption system and compensating for the redundancy of the verification elements was substantiated. The method for cryptographic transformation of data based on the gamma sequence was developed, which is formed by combining numbers from different sources of dynamical chaos generators. The efficiency criterion was introduced for the integrated information transformation method.

Compression, encryption, encoding and modulation at the transmitter side and reverse process at the receiver side are the major processes in any wireless communication system. All these steps were carried out separately before. But, in 1978 R. J. McEliece had proposed the concept of combining security and channel encoding techniques together. Many schemes are proposed by different researchers for this combine approach. Sharing the information securely, but at the same time maintaining acceptable bit error rate in such combine system is difficult. In this paper, a new technique for robust and secure wireless transmission of image combining Turbo Product Code (TPC) with chaotic encryption is proposed. Logistic map is used for chaotic encryption and TPC for channel encoding. Simulation results for this combined system are analyzed and it shows that TPC and chaotic combination gives secure transmission with acceptable data rate.

Sophisticated technologies realized from applying the idea of biometric identification are increasingly applied in the entrance security management system, private document protection, and security access control. Common biometric identification involves voice, attitude, keystroke, signature, iris, face, palm or finger prints, etc. Still, there are novel identification technologies based on the individual's biometric features under development [1-4].

The E-mail messaging is one of the most popular uses of the Internet and the multiple Internet users can exchange messages within short span of time. Although the security of the E-mail messages is an important issue, no such security is supported by the Internet standards. One well known scheme, called PGP (Pretty Good Privacy) is used for personal security of E-mail messages. There is an attack on CFB Mode Encryption as used by OpenPGP. To overcome the attacks and to improve the security a new model is proposed which is "Secure Mail using Visual Cryptography". In the secure mail using visual cryptography the message to be transmitted is converted into a gray scale image. Then (2, 2) visual cryptographic shares are generated from the gray scale image. The shares are encrypted using A Chaos-Based Image Encryption Algorithm Using Wavelet Transform and authenticated using Public Key based Image Authentication method. One of the shares is send to a server and the second share is send to the receipent's mail box. The two shares are transmitted through two different transmission medium so man in the middle attack is not possible. If an adversary has only one out of the two shares, then he has absolutely no information about the message. At the receiver side the two shares are fetched, decrypted and stacked to generate the grey scale image. From the grey scale image the message is reconstructed.