We introduce TinySec, the first fully-implemented link layer security architecture for wireless sensor networks. In our design, we leverage recent lessons learned from design vulnerabilities in security protocols for other wireless networks such as 802.11b and GSM. Conventional security protocols tend to be conservative in their security guarantees, typically adding 16--32 bytes of overhead. With small memories, weak processors, limited energy, and 30 byte packets, sensor networks cannot afford this luxury. TinySec addresses these extreme resource constraints with careful design; we explore the tradeoffs among different cryptographic primitives and use the inherent sensor network limitations to our advantage when choosing parameters to find a sweet spot for security, packet overhead, and resource requirements. TinySec is portable to a variety of hardware and radio platforms. Our experimental results on a 36 node distributed sensor network application clearly demonstrate that software based link layer protocols are feasible and efficient, adding less than 10% energy, latency, and bandwidth overhead.

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The Secure Shell (SSH) protocol is one of the most popular cryptographic protocols on the Internet. Unfortunately, the current SSH authenticated encryption mechanism is insecure. In this paper we propose several fixes to the SSH protocol and, using techniques from modern cryptography, we prove that our modified versions of SSH meet strong new chosen-ciphertext privacy and integrity requirements. Furthermore, our proposed fixes will require relatively little modification to the SSH protocol or to SSH implementations. We believe that our new notions of privacy and integrity for encryption schemes with stateful decryption algorithms will be of independent interest.

The Secure Shell (SSH) protocol is one of the most popular cryptographic protocols on the Internet. Unfortunately, the current SSH authenticated encryption mechanism is insecure. In this paper, we propose several fixes to the SSH protocol and, using techniques from modern cryptography, we prove that our modified versions of SSH meet strong new chosen-ciphertext privacy and integrity requirements. Furthermore, our proposed fixes will require relatively little modification to the SSH protocol and to SSH implementations. We believe that our new notions of privacy and integrity for encryption schemes with stateful decryption algorithms will be of independent interest.

The Secure Shell (SSH) protocol is one of the most popular cryptographic protocols on the Internet. Unfortunately, the current SSH authenticated encryption mechanism is insecure. In this paper we propose several fixes to the SSH protocol and, using techniques from modern cryptography, we prove that our modified versions of SSH meet strong new chosen-ciphertext privacy and integrity requirements. Furthermore, our proposed fixes will require relatively little modification to the SSH protocol (or to SSH implementations). We believe that our new notions of privacy and integrity for encryption schemes with stateful decryption algorithms will be of independent interest.

Inherent to the wireless sensor networks are the two major problems of the broadcasting vulnerability, the limited computational capability and power budget. Even though security is a must in most applications, current sophisticated security protocols are not amenable to the primitiveness of the sensors. In this paper, we introduce a novel security protocol for wireless network of sensors that is very secure, yet simple and efficient. At the core of our security protocol is a simple and fast stream cipher cryptosystem that utilizes permutation vectors as encryption keys, forcing an intruder to a brute-force time complexity of Ω(2 n). In addition, our mechanism alleviates the effect of sensor capture, via its synchronized re-keying feature. In addition to the encryption efficiency, our system utilizes the group deployment of newly joining sensors for sensors power budgeting considerations. Experimental results show very promising future of our system in the wireless networks domain, excelling over other peers of modern cryptosystems (AES, DES, TripleDES), especially in the power budget arena.

The Datagram Congestion Control Protocol (DCCP) is a transport protocol that provides bidirectional unicast connections of congestion-controlled unreliable datagrams. DCCP is suitable for applications that transfer fairly large amounts of data and that can benefit from control over the tradeoff between timeliness and reliability.

Due to the rapid evolution of networking and electronic capabilities, the use of wireless devices is becoming ubiquitous. Most of the wireless networks have fixed infrastructure and requires higher data rates. Due to high data rate in wireless networks the Transmission Control Protocol (TCP) performance has a broad and significant impact on data applications, and is essential towards massive deployment of service-providing agents and their widespread social acceptance. Wireless link losses result in poor TCP throughput since losses are professed as congestion by TCP. In order to increase the throughput, a Multi agent System (MAS) named Reusable Environment for Task-Structured Intelligent Networked Agents (RETSINA) has been introduced. This agent has the capability to reduce the impact of losses on TCP throughput and latency. In this work, we considered a video game application in which a networked virtual environment with high fidelity sound and video is created. Moreover, to efficiently use the video game application in a wireless environment, an Unreal Tournament Semi-Automated Force (UTSAF) multi agent has been proposed. UTSAF is a middleware written to take advantage of the power of gaming application systems by allowing them to participate in distributed simulations. The personal agent communicates wirelessly, in order to find the most appropriate option to serve the user. In addition, we comprehensively evaluated the performance of TCP with and without these multi agent platforms as technology choice and investigated its efficiency in a number of cases. We find that the simulations with the multi agent can reach the TCP throughput by as much as 95 % and the latency get reduced by 1-2 % as the simulation time steps in for every 100 seconds.