Performance analysis of an ISMA DS-CDMA packet data network

The efficiency of MAC protocols for a packet switching DS-CDMA network strongly depends on the offered traffic statistic. For bursty sources where transmission needs are restricted to short message lengths, a protocol such as S-ALOHA can be efficient. However, for longer messages, a reduction in the randomness is required in order to improve the system performance. This improvement can be provided by a protocol such as ISMA when combined with the DS-CDMA technique. In this paper an analytical approach to modeling the resulting ISMA CDMA scheme is presented, and some design issues regarding the number of codes to be used are presented.Peer ReviewedPostprint (published version

Badger - A Fast and Provably Secure MAC

We present Badger, a new fast and provably secure MAC based on universal hashing. In the construction, a modified tree hash that is more efficient than standard tree hash is used and its security is being proven. Furthermore, in order to derive the core hash function of the tree, we use a novel technique for reducing $\Delta$-universal function families to universal families. The resulting MAC is very efficient on standard platforms both for short and long messages. As an example, for a $64$-bit tag, it achieves performances up to 2.2 and 1.2 clock cycles per byte on a Pentium III and Pentium 4 processor, respectively. The forgery probability is at most $2^{-52.2}$

Ascon PRF, MAC, and Short-Input MAC

The cipher suite Ascon v1.2 already provides authenticated encryption schemes, hash, and extendable output functions. Furthermore, the underlying permutation is also used in two instances of Isap v2.0, an authenticated encryption scheme designed to provide enhanced robustness against side-channel and fault attacks. In this paper, we enrich the functionality one can get out of Ascon\u27s permutation by providing efficient Pseudorandom Functions (PRFs), a Message Authentication Code (MAC) and a fast short-input PRF for messages up to 128 bits

Design Aspects of An Energy-Efficient, Lightweight Medium Access Control Protocol for Wireless Sensor Networks

This document gives an overview of the most relevant design aspects of the lightweight medium access control (LMAC) protocol [16] for wireless sensor networks (WSNs). These aspects include selfconfiguring and localized operation of the protocol, time synchronization in multi-hop networks, network setup and strategies to reduce latency.\ud The main goal in designing a MAC protocol for WSNs is to minimize energy waste - due to collisions of messages and idle listening - , while limiting latency and loss of data throughput. It is shown that the LMAC protocol performs well on energy-efficiency and delivery ratio [19] and can\ud ensure a long-lived, self-configuring network of battery-powered wireless sensors.\ud The protocol is based upon scheduled access, in which each node periodically gets a time slot, during which it is allowed to transmit. The protocol does not depend on central managers to assign time slots to nodes.\ud WSNs are assumed to be multi-hop networks, which allows for spatial reuse of time slots, just like frequency reuse in GSM cells. In this document, we present a distributed algorithm that allows nodes to find unoccupied time slots, which can be used without causing collision or interference to other nodes. Each node takes one time slot in control to\ud carry out its data transmissions. Latency is affected by the actual choice of controlled time slot. We present time slot choosing strategies, which ensure a low latency for the most common data traffic in WSNs: reporting of sensor readings to central sinks

A security architecture for personal networks

Abstract Personal Network (PN) is a new concept utilizing pervasive computing to meet the needs of the user. As PNs edge closer towards reality, security becomes an important concern since any vulnerability in the system will limit its practical use. In this paper we introduce a security architecture designed for PNs. Our aim is to use secure but lightweight mechanisms suitable for resource constrained devices and wireless communication. We support pair-wise keys for secure cluster formation and use group keys for securing intra-cluster communication. In order to analyze the performance of our proposed mechanisms, we carry out simulations using ns-2. The results show that our mechanisms have a low overhead in terms of delay and energy consumption

A Lightweight Medium Access Protocol (LMAC) for Wireless Sensor Networks: Reducing Preamble Transmissions and Transceiver State Switches

In this paper, we present an energy-efficient medium access protocol designed for wireless sensor networks. Although the protocol uses TDMA to give nodes in the WSN the opportunity to communicate collision-free, the network is self-organizing in terms of time slot assignment and synchronization. The main goal of the medium access protocol is to minimize overhead of the physical layer. The protocol reduces the number of transceiver state switches and hence the energy wasted in preamble transmissions. The protocol is compared to SMAC and EMACs by simulation. The LMAC protocol is able to extend the network lifetime by a factor 2.4 and 3.8, compared to EMACs and SMAC respectively