Security protocols & platform for wsn based medical applications
- 1. Security protocols & platform FOR WSN BASED MEDICAL APPLICATIONS -AVIJIT MATHUR SUPERVISOR: DR. THOMAS NEWE
- 2. Overview WSN: Nodes collected and organized in some fashion in order to make a cooperative network. Usage: Monitoring of patients wirelessly. (Routine/emergency/mass causality) thereby providing healthcare services. As the population increases there is a need for continuous medical monitoring. Patients monitored wirelessly has several advantages. Traditional wired methods do not allow mobility with the added difficulty of time constraints. Provide a secure, reliable and energy-efficient Wireless Sensor Network for medical devices.
- 3. In Home/hospital architecture Base StationRepeater Access point 1 Access point 2 Access point 3 GSM/3g/ 4g WiFi WiMAX ZIGBEE BLE
- 4. Topologies Star Mesh: Hierarchical tree Clustered Hierarchical Star Topology Partial Mesh Topology Hierarchical Tree Clustered HierarchicalCluster Head Central Hub/Switch Gateway Nodes Sensor Nodes Source: A Performance Comparison of Different Topologies for Wireless Sensor Networks by Akhilesh Shrestha and Liudong Xing
- 5. ZIGBEE Bluetooth Low energy Wi-Fi 4G Range 10-100 m >60m (10m for Classic BT) Depends on specification In Kilometers Power Low Very Low (High for classic BT and medium for others) High (variable for WiFi Direct) High Entries 254 (>64000 per network) 2 Billion (Classic: 7) Depends on no. of IP addresses - Latency Low 3 ms (compared to 100ms in classic BT) Variable - Self healing Yes - Yes Yes Topologies Mesh, Star and Cluster- tree Star Star, Point-to-Point Ring Data transmission rate Up to 250Kbps 1Mbps (BT v4.0: 25Mbps) 11Mbps & 54Mbps (250 Mbps: WiFi Direct) 100Mbps & 1Gbps(fixed access) Bandwidth 2.4GHz, 915MHz & 868 MHz 2.4 GHz only (BT + HS: 6-9 GHz) 2.4, 3.6 & 5 GHz Similar to WiFi Transmission technique DSSS DS/FA? Adaptive FHSS (Classic BT: FHSS) DSSS, CCK & OFDM OFDMA
- 6. IEEE 802.15.6 New standard specified for Wireless Body Area Networks (WBANs) Extremely low power, good data rate and safety compliant. Flexible frequencies => selecting the right physical layer very important MICS and WMTS do not support high data rate while ISM band supports high data rate at the cost of interference. PHY layers Security levels Source :An Overview of IEEE 802.15.6 Standard (Invited Paper) Kyung Sup Kwak, Sana Ullah, and Niamat Ullah; UWB-ITRC Center, Inha University; 253 Yonghyun-dong, Nam-gu, Incheon (402-751), South Korea Table Source:Body Area Networks Arif Onder ISIKMAN, Loris Cazalony, Feiquan Chenz, Peng Lix Chalmers University of Technology, SE-412 96, Gothenburg, Sweden IEEE 802.15.4 / ZigBee IEEE 802.15.6 Range 10-100m 2-5m Data rate 20,40 & 250 Kbps Few Kbps – 10 Mbps Power 25-35mW 0.01 mW (stand by), 40mW (active) Entries 65535 devices 256 devices per network
- 7. Security & Reliability Security services: Authentication, access control, data confidentiality, integrity and Non-repudiation. Reliability depends on two main factors: network connectivity and sensing coverage. Security is very important as the technology may be vulnerable to attacks Traditional security mechanisms (PKI) cannot be used. Semantic security Secure routing & storage are most important Source: Integrated Modeling for Wireless Sensor Networks by Liudong Xing, Ph. D., University of Massachusetts, Dartmouth & Howard E. Michel, Ph.D., University of Massachusetts, Dartmouth
- 8. Security protocols TinySec MiniSec SPINS: SNEP & uTesla LiSP MAC SIA
- 9. Security Mechanism Steganography: Channel is hidden under the Physical layer to provide covert data transmission Cryptography: Encryption & authentication mechanisms Key management: Global, pair-wise node, pair-wise group & individual Localization: Geographically detect a malicious node Trust management: Select route based on trustworthy nodes Data Partitioning 6 6 6 6 7 7 7 6 Periodic key generation Data: D D1 D2 D3 D1 D1 D2 D3 D3 Source: Wireless Sensor Network Attacks and Security Mechanisms : A Short Survey David Martins and Hervé Guyennet Computer Science Department, University of Franche-Comté, France
- 10. Energy management Energy consuming layers Use VCO based radio architecture since it is: Robust to interference Allows communication at different carrier frequencies Better sleep synchronization Uses Flash over SRAM memory Efficient programming techniques Collision avoidance Idle listening periods must be reduced Routing: with the usage of real-time protocols, reduce the size of routing tables Clustering: Hierarchical clustering Data gathering
- 11. Issues & Challenges Privacy & security Trust Coverage Communication delay Need for reliable, fault tolerant, self-healing and organising cluster-scheme for key distribution Choosing the right blend of encryption and authentication schemes Movement of patient is challenging with regards to architecture, coverage and routing. Decentralized security mechanism.
- 12. Findings Research into network topologies and clustering algorithms. Securing both the nodes and the communication network. Group key distribution techniques. WSNs require node scalability and mobile agent. Sensors may capture confidential data. Motes must authenticate the stored public key of Base station. In the future it may be possible for patients to interpret their results on a PDA/desktop.
- 13. Findings Key management schemes to be further researched. Nodes should automatically decide on a routing strategy. Medical environment may call for high reporting times from the nodes (emergency). Reporting of failed nodes and healing of the network is important. Connectivity: USB, Ethernet, RS232 + WiFi, ZigBee, Bluetooth & cellular. Machine learning algorithm can act as a mediator. Image source: Medical Applications based on Wireless Sensor Networks by Stanković, Stanislava
- 15. Motes Tmote Sky Tmote sky: http://insense.cs.st-andrews.ac.uk/examples/ Micaz: http://www.cse.chalmers.se/~larandr/master.html Shimmer: http://www.eecs.Harvard.edu/~mdw/proj/codeblue Shimmer Micaz
Editor's Notes
- #5: Simulations show that transmission energy is equivalent to receive energy when distance is short or/and radio electronics energy is high. Direct transmission is more efficient on global scale than minimum transmission energy (MTE) routing. Therefore we use star topology for BANs