Efficiency analysis of public key management scheme for wsn using TinyOS
Efficiency Analysis of public key management scheme for WSN on TinyOS<br />
Introduction to WSN<br /> A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants, at different locations.<br />Characteristics of WSN <br /> Very Limited Resources<br /> Unreliable Communication<br /> Unattended Operation<br />
Introduction to TinyOS<br /> It is a free and open source component-based operating system and platform targeting wireless sensor networks (WSNs). TinyOS is an embedded operating system written in the nesC programming language as a set of cooperating tasks and processes.<br /> It provides interfaces and components for common abstractions such as packet communication, routing, sensing, actuation and storage.<br /> Its main methodology is “hurry up and sleep” , this way it can save power.<br />
KEY MANAGEMENT<br /> Key management deals with the secure generation, distribution, and storage of keys. Secure methods of key management are extremely important.<br />Goals of key management:<br />The protocol must establish a key between all sensor nodes that must exchange data securely.<br />Node addition / deletion should be supported.<br />It should work in undefined deployment environment.<br />Unauthorized nodes should not be allowed to establish communication with network nodes.<br />
Public key-based key management<br /> In this scheme there is a Key pair for each node i.epublic+private<br /> Each node will have its own public and private keys. Public key can be known via sending message but private is not. Private key is confidential and used to exchange the data securely.<br />Pre-load all pair-wise keys<br /> Each two nodes can compute unique pair wise key from their public and private values.<br /> Each node needs to store (n-1) keys in its memory for n nodes in network. <br />
Pre-Load Distribution Key<br /> All nodes will have preloaded keys. Basestation will communicate to all nodes via different keys which is already loaded in all nodes i.e all nodes will have a pool of keys and every communication will be carried out with that key on which two nodes will agree on common key from pool of keys.<br />5<br />4<br />6<br />Base station<br />0<br />3<br />7<br />2<br />8<br />1<br />
Process <br />Step 1:Basestation will send a key from a pool of keys to node i which is encrypted by common network key.<br />Step 2:Node i will receive the message and decrypt the message using network key.<br />Step 3:After that, node i match the decrypted key in its pool of keys. If node i find a match of received key and it is free i.e it is not paired with any other node then it will mark that key as paired with basestation.<br />Step 4:If node i doesn’t find a match or key is not free then it send failure message to BS.<br />
Step 4:If node i find match then node i will send success message to BS then BS will paired that key with node i in its pool of key.<br />Step 5:If BS receive a failure message then it will send another free key from pool of key to node i until it is not receiving the success message.<br />BS<br />Node i<br />A1 2<br />A2 -1<br />A3 -1<br />A4 -1<br />A5 -1 <br />A6 -1<br />A1 -1<br />A2 -1<br />A3 -1<br />A4 -1<br />A5 -1 <br />A6 -1<br />
Process of Public key-based key management <br /><ul><li>each side of the communication generates a private key(letter A).
Each side then generates a public key (letter B), which is a derivative of the private key.
The two systems then exchange their public keys. Each side of the communication now has their own private key and the other systems public key (letter C).
The Diffie-Hellman protocol generates “shared secrets” – identical cryptographic key shared by each side of the communication.</li></li></ul><li>Work Completed till now <br />TinyOS Installation & setting its Environment Variables.<br />WSN network is simulated in TOSSIM simulator with tinyvizgui.<br />Tossim simulates nesC applications.<br />
Simulating public-key management scheme<br />Calculating energy consumption per node in the scheme<br />
Work to be done<br />Efficiency Analysis<br />1 Pair wise key distribution<br />let number of total steps in finding and distributing key for node pair is =m<br /> Active + Sampling 0.0037 J/sample<br /> then energy consumption will be = m*0.0037J <br /> Space Requirement = N-1 keys per node (N is total no of nodes) <br />2 Public key-based<br />let number of total Steps in calculating the public and private key for node i is = n<br />now the energy consumption will be = n*0.0037J<br /> Space requirement = 2 keys per node<br />
After calculating the energy of both public key and pre-load key for different number of nodes we will plot the energy Vs node graph for a n node system which will clearly show the efficient key management scheme. to be calculatedEnergy<br /> per node <br />