Department of Computer System Architecture (2014 - Present)
Electrical Engineering
Dep. of Electrical & Computer Engineering, Isfahan University of Technology, Isfahan, Iran
Computer Architecture
Dep. of Electrical & Computer, Isfahan University of Technology, Isfahan, Iran
Computer Eng.
Department of Computer Engineering, Sharif University of Technology, Tehran, Iran
Research field: Mobile PenTest
Expert: Azadeh Mokhtarpoor
Phone: 82883202
Address: Floor 1, ECE Dep.
Subscriber authentication is a primitive operation in mobile networks required by each operator prior to offering any service to end users. In this paper, we propose a novel blockchain-based Authentication and Key Agreement (AKA) protocol for roaming services in 5G networks. Each Home Network (HN) creates its own smart contract and publishes its address to inform other operators who want to offer roaming services to HN subscribers. All subsequent communication between the HN and Serving Network (SN) is done by calling the function of this smart contract. The proposed protocol eliminates the need for a secure channel between the HN and SN, which is a primary requirement of current 5G AKA protocols. In practice, a secure channel requires the
In this paper, we propose INCP, inter-flow network coding protocol, for wireless mesh networks. INCP is designed with the concept of Layered Approach. It acts as a distinct layer above the MAC and has close cooperation with IP layer. INCP exploits the opportunities of network coding through multiple unicast sessions to decrease the number of transmissions, thereby increasing the aggregated throughput. Unlike most prior work that is mainly theoretical, INCP addresses the practical issues of network coding such as impact of lossy links, enabling/disabling RTS/CTS mechanism, packet size and its variation. We consider a retransmission mechanism to ensure a reliable broadcasting. We analyze the cost of this approach by providing a theoretical fo
This paper addresses the problem of inter-flow network coding for unicast sessions in lossy channel wireless networks. In spite of decreasing the number of transmissions, network coding intuitively increases the sensitivity of nodes to lost packets. First of all, coded packets carry more information than native packets and thus losing a coded packet prohibits a series of dependent nodes from decoding their intended packets. Secondly, for the scheme with opportunistic listening, it is necessary for some of the nodes to overhear the transmission of their neighbors. Thus, successful decoding requires overhearing of the corresponding packet (s) in addition to correct reception of unicast and broadcast transmissions.
In this paper, first, we propose Star-NC, a new network coding (NC) scheme for multiple unicast sessions in an n-input n-output star structure. Then, we evaluate the network throughput of this coding scheme in wireless mesh network over the traditional non-NC transmission. Our scheme benefits from the proximity of all the nodes around the relay node and employs a more general form of overhearing different from other schemes such as COPE. We found that the gain of our NC scheme depends on both the star size and the routing pattern of the unicast transmissions. Based on this, we identify both the situations which the maximum gain is achievable and a lower bound for the expected value of the gain in the case of random routing pa
Throughput limitation of wireless networks imposes many practical problems as a result of wireless media broadcast nature. The solutions of the problem are mainly categorized in two groups; the use of multiple orthogonal channels and network coding (NC). The networks with multiple orthogonal channels and possibly multiple interfaces can mitigate co-channel interference among nodes. However, efficient assignment of channels to the available network interfaces is a major problem for network designers. Existing heuristic and theoretical work unanimously focused on joint design of channel assignment with the conventional transport/IP/MAC architecture. Furthermore, NC has been a prominent approach to improve the throughput of unic
This paper introduces a novel vertical handoff method in which the number of signaling and registration processes is lowered as a result of reduced utilization of home agent and correspondent nodes while users are mobile. Throughput performance of the integrated network is improved by reducing handoff delays and packet losses. We also decrease the system energy by estimating user locations in comparison with the WLANs to decrease interface ontimes. Performance and delay results are presented to demonstrate the effectiveness of the proposed scheme.
We propose a new vertical handoff method in which the number of signaling and registration processes is lowered as a result of reduced utilization of home agent and correspondent nodes while users are mobile. Throughput performance of the integrated network is improved by reducing handoff delays and packet losses. Special conditions such as boundary condition also considered. Performance and delay evaluations which done by ns-2 are presented to demonstrate the effectiveness of the proposed scheme.
Fast Data Encryption (FDE) is a new symmetric block cipher which has a DES-like structure. FDE has been designed with an increased key length, increased key scheduling complexity and an improved round function which can be executed in parallel. FDE uses eight Substitution Boxes (S-boxes) in the round function to provide confusion. In this paper, we present the FDE structure and an algorithm to construct a set of strong S-boxes. Eight suitable S-boxes from this set are suggested for use with FDE.
FDE is a block cipher which has a Substitution-Permutation (SP) network structure. In this paper, the security and performance of this cipher are discussed. We show that FDE has a good security margin against differential and linear attacks. The best differential 15-round characteristic of FDE has a probability of success of less than 2− 140. Moreover, for linear cryptanalysis we show that the best linear probability of success is less than 2− 55, which requires at least 2110 plaintextciphertext pairs, which is greater than all possible pairs. We also present two fast software implementations of FDE which eliminate the permutations in the round functions. In the first method, this is achieved by merging the permutations with the s-box t
In this paper, we consider 5G as an evolution of 4G, thus we propose logical connections between LTE-A entities such as SGW, PDN firstly. Then, we present a new configuration and accordingly data/control realization of 5G EPS (Evolved Packet System) based on a carrier-grade hypervisor and an intelligent core server (IC server) to provide virtualization and flexibility to the network. In addition, we define two new entities hAN (heterogeneous access network) and TNT-Gateway (TENANT Gateway) for access and core, respectively and define their functions and data/signaling connections. Some important advantages of these configurations are: 1) cost reduction, 2) network efficiency improvement, and 3) increase of network flexibility and service av
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