Key management in wireless
sensor networks
Kevin Wang
About WSN
• What is wireless sensor networks?
– Definition
• Inexpensive, limited resources…
– Constraints
• Limited power, computing ability, memory size and
communication protocol
– Application
• Military or hospital…
For example
• Berkeley-designed MICA2
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8 Mhz Atmel CPU
Instruction memory size is 128 kb
Data usage is 4 kb of RAM
Flash memory size is 512 kb
19.2 kbps application bandwidth up to a range of 10–20
meter
– At full power the MICA2 will run for about two weeks
before exhaustion and up to one year using sleep modes
– Tiny OS
Security Risks in Wireless
Sensory Networks
• Eavesdropping
K
K
– Confidentiality
• Packet Injection
– Access control
– Integrity
• Jamming
• Replay
• Denial of Service
K
K
Adversary
Problems
• Focus on
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Key management
Clustering and Routing problem
Power consumption
Handoff problem
• Mobile node
Key management for WSN 1/4
• Models
– Hierarchical and Distributed WSN
Key management for WSN 2/4
• Communication types
– Unicast
• Nodes to headers
• Nodes to nodes
• Header to header
– Multicast
• Header to nodes
– Broadcast
• Server to nodes
• Server to headers
Key management for WSN 3/4
• Key predistribution
types
– Deterministic
– Probabilistic
– Hybrid
Key management for WSN 4/4
• Dynamic key generation algorithms for distributing
– Pair-wise
– Group-wise
– Network-wise
Clustering problem
• Cluster problem
– Random deployment
• Need an efficient
algorithm to cluster
– Use deployment
knowledge
• Impracticable or
infeasible: DDHV-D
scheme
Routing problem
• Routing problem
– Shortest path is good?
– Find dynamic paths to
reach max-life of WSN
– Solution:
• Static
– GA, NN, …
• Mobile
– Dynamic tiny GA…
Power consumption
• In WSN, the energy is an important dominated factor
• Deliver messages will consumption much energy
– Deliver one bit : execute one instruction = 200~2900 : 1
• But if fix the key function then the entire WSN will be
weakness.
• So we consider power constraint and propose a novel
scheme
– Dynamic key-generation function
– And the key function fulfill the power constraint
Handoff problem
• No move no handoff
• Mobile nodes
– Headers verse nodes
– In mobile WSN, as
nodes moving, then the
secure problem will be
more important.
?
Question
Our scheme