Abstract In spite of the existence of more attack-resistant authentication schemes, passwords are the most popular means of access control. They also constitute the first line of defence in cyber-based security systems. Unfortunately, the twin problem of multiplicity of passwords combined with destructive human factors has resulted in numerous rules which have made password management cumbersome. The resultant evasive tendency on... In spite of the existence of more attack-resistant authentication schemes, passwords are the most popular means of access control. They also constitute the first line of defence in cyber-based security systems. Unfortunately, the twin problem of multiplicity of passwords combined with destructive human factors has resulted in numerous rules which have made password management cumbersome. The resultant evasive tendency on the part of users has created a divergence among security experts. Using a survey, this paper examines the level of password security awareness in Africa, vis a vis the current divergence among security engineers as regards the rules governing best practices in the use of passwords: should they be written down or memorized; changed frequently or remain permanent? It also proposes a possible way out in respect of the password security purgatory phenomenon. It is posited that, in order to enhance password security, there should be a delicate balance between having enough rules to maintain good security and not having too many rules that would compel users to take evasive actions; i.e., human factors should be given priority over technological factors. The password security survey further confirmed the fear that most Internet users are inclined to choosing passwords that are both meaningful and easily remember-able. Similarly, in Africa, and probably most developing countries, senior executives are less security conscious compared to their subordinates, as regards password related matters. The paper proposes the use of the (k, n)- Threshold Scheme, such as the Shamir’s secret-sharing scheme, to enhance the security of the password repository. This presupposes an inclination towards writing down the password: they could be stored securely, along with other valuables, even where other modern technological facilities are not available. Read More Read Less

Abstract Establishing a common secret key between two or more entities is an essential component of any security system. In this paper, the problem of establishing a shared session key in an authenticated way is addressed. The proposed key agreement protocols support explicit authentication. The protocols are designed in such a way that permits a trusted third party, such as a... Establishing a common secret key between two or more entities is an essential component of any security system. In this paper, the problem of establishing a shared session key in an authenticated way is addressed. The proposed key agreement protocols support explicit authentication. The protocols are designed in such a way that permits a trusted third party, such as a firewall, to verify the identities of the parties involved in a key agreement session. This is reduces the computational burden at the end-user side, which can be a device with limited capabilities. The proposed protocols have been implemented, based on the PBC library provided by Stanford University, to ensure their correctness, the ease of their practical use and their timeliness. A comparative study of the proposed protocols to other protocols in literature revealed the superiority of the proposed protocols from the security viewpoint at the cost of an acceptable increase in the computational burden. Read More Read Less

Abstract Enterprise organizations expend significant resources on security countermeasures to make sure that their networks are protected. Risk analysis is one area of information security research that aims to help organizations in making quick decisions and preventing attackers from compromising their networks. Here we use attack graphs to both display possible attack vectors in simple systems and as an analysis tool... Enterprise organizations expend significant resources on security countermeasures to make sure that their networks are protected. Risk analysis is one area of information security research that aims to help organizations in making quick decisions and preventing attackers from compromising their networks. Here we use attack graphs to both display possible attack vectors in simple systems and as an analysis tool for more complex systems. This can be used within a risk analysis strategy. System administrators face constant challenges when they have to decide what countermeasures they must deploy taking into account the minimum budget to deploy a set of countermeasures. The attack graph approach used here aims to minimize the cost of deploying countermeasures. Specifically we develop an approach to find the minimum cut set in dependency attack graphs using a genetic algorithm (GA). We also combine the GA with a local search algorithm to improve the performance of the GA. The minimum cut set is a natural graph representation describing a set of security countermeasures that prevent attackers reaching their targets. More importantly, this work considers shared security countermeasures that are deployed in more than one place in the attack graph. Therefore, there may be one security countermeasure that can fix multiple vulnerabilities. Alternatively, there may be a vulnerability or an exploit in the attack graph that can be stopped by one of multiple countermeasures. The work shows that the problem maps naturally to a binary encoded GA and gives good results without the need to deploy problem specific GA operators. Read More Read Less

Abstract This paper propose some solutions to improve the performance of terminals mobile transmissions at high speeds, low cost and low power consumption. Indeed, the increase in rates implies that the transmission channels are more difficult, making the task of receivers more difficult. , we are interested in solving the classical problem of detection of a linear mixture of Gaussian noise... This paper propose some solutions to improve the performance of terminals mobile transmissions at high speeds, low cost and low power consumption. Indeed, the increase in rates implies that the transmission channels are more difficult, making the task of receivers more difficult. , we are interested in solving the classical problem of detection of a linear mixture of Gaussian noise for MIMO OFDM telecommunication systems from a noisy observation of an input signal mixed with a known matrix representing the behavior of the channel, we seek the vector minimizing the Euclidean distance between the noisy output and the noiseless one. MIMO OFDM systems have large frequency diversity. In this context, we investigate in a first part in the study of performance of conventional equalizers (ML, ZF, MMSE…). In a second part, we propose a detection algorithm with near-optimal performance in terms of bit error rate BER very close to ML called PSO (Particular Swarm Optimization) for its complexity relatively small compared to other detectors. Read More Read Less

Abstract A new way to represent Image consists in numbering all possible pixel combinations. Instead of defining it by a matrix of pixels, the number of the pixel combinations that corresponds to the given image is a unique identifier of this image. To store the image in a memory, we need only to write this number in a file. This new... A new way to represent Image consists in numbering all possible pixel combinations. Instead of defining it by a matrix of pixels, the number of the pixel combinations that corresponds to the given image is a unique identifier of this image. To store the image in a memory, we need only to write this number in a file. This new method has several intrinsic advantages such as compression and encryption. Read More Read Less