Abstract In this paper, we present a new approach of image encryption using a stream ciphering model. The proposed pseudo-random number generator is based on combination of elementary one-dimensional cellular automata (CA)with elliptic curves. Indeed, we explored the transitions of the CA with the coordinates of a point belonging to an elliptic curve. The outcome from another point was multiplied by a scalar. CA... In this paper, we present a new approach of image encryption using a stream ciphering model. The proposed pseudo-random number generator is based on combination of elementary one-dimensional cellular automata (CA)with elliptic curves. Indeed, we explored the transitions of the CA with the coordinates of a point belonging to an elliptic curve. The outcome from another point was multiplied by a scalar. CA offers the qualities of ambiguity and chaos, so by combining the two concepts, we have constructed a PRNG that generates a key stream, used by the way in our approach. This work constitutes an analogy to works that involved dynamic systems like logistics map with elliptic curves. The proposed PRNG shows good cryptographic properties,and high security level that depends in the difficulty to solve the discrete logarithm problem on elliptic curves (ECDLP). The proposition evaluated the images encryption, and it turns out that obtained results are very promising. Read More Read Less

Abstract A Public-Key System (especially Identity-Based Encryption) is said to be secure if it is proved to be secure against simulation studies, taking into account the purpose of the attacker and the model used. Among the goals there are indistinguished IND and semantic goal, regarding the models, we quote Chosen Plaintext Attack (CPA),Chosen Ciphertext Attack (CCA). Their combination gives INDistinguishability under Chosen Plaintext Attack... A Public-Key System (especially Identity-Based Encryption) is said to be secure if it is proved to be secure against simulation studies, taking into account the purpose of the attacker and the model used. Among the goals there are indistinguished IND and semantic goal, regarding the models, we quote Chosen Plaintext Attack (CPA),Chosen Ciphertext Attack (CCA). Their combination gives INDistinguishability under Chosen Plaintext Attack (IND-CPA), semantic-CPA, semantic- CCA, IND-CCA. The study considered as strong and concretizing for ideal security is IND-CCA, for the IBE we talk about IND-ID-CCA (also: semantics-ID-CPA, semantics-ID-CCA, IND-ID-CPA) . This IND-ID-CCA (as well as the others) belongs to a full domain whose identity to attack is declared in the challenge. This IND-ID-CCA (as well as the others) belongs to a full domain whose identity to attack is declared in the challenge. A so-called weak type is introduced in 2003 by Canetti et al [1] and is called selective-ID. In this model, the target identity to be attacked is declared in the beginning that is in the Setup. It is proved in [2] that the transition from selective ID to a complete domain requires a multiplication by N (produces a degradation in the security). In spite of this weakness, in Eurocrypt 2004 Boneh and Boyen [2] proposed two crypto systems under this type, these are the only ones known in the literature drawn up in the same type. The first is a HIBE based on the DBDHP (Decisional of Diffie and Hellman Problem) problem and under the Commutative Blinding approach it is known by BB1. While the second is an IBE Under the Exponent-Inversion approach named BB2, it is based on Dq-BDHIP (Decisional q- Invertible of Bilinear Diffie and Hellman Problem). By combining the idea of the inverse used in BB2 and remaining in the Commutative Blinding approach,In this paper we will propose our New IBE scheme [5] which will be efficient than BB1 (IBE version [4]) and even BB2. Read More Read Less

Abstract In recent years, many computer forensics theoretical methods have been developed to provide efficient means to counter computer crimes. Computer evidence must be accurate and thorough. A design of architecture of a forensics system is given in this design, and the log data is the key Computer evidence to analyse. One of the key issues this paper tries to resolve is the log-data... In recent years, many computer forensics theoretical methods have been developed to provide efficient means to counter computer crimes. Computer evidence must be accurate and thorough. A design of architecture of a forensics system is given in this design, and the log data is the key Computer evidence to analyse. One of the key issues this paper tries to resolve is the log-data integrity. In the system, CES algorithm is used to protect and verify the integrity of log data. Another key issue is how to analyse the computer evidence accurately. A timestamp-based multi-characters log analysis method is also discussed in this paper. This method is to realize and tag the relationship of time-line sequence which is a reasonable way to identify the user’s behaviour. The result comes out that the forensics technique will be more integrated and thorough. Read More Read Less