10-04-2017, 08:35 PM
SKEW: An Efficient Self Key Establishment Protocol for
Wireless Sensor Networks
INTRODUCTION:
Wireless Sensor Networks architectures can generally be organized in two
ways: distributed and hierarchal. A hierarchical WSN has a network hierarchy based on factors like power and memory among the sensor nodes. The Cluster heads collect local or received data and send them to base stations. Cryptography keys in the protocols used in WSNs are transmitted within nodes via messages and thus incur heavy overheads. A sender node has 2 options :either send 2
messages to a receiver node, one for transmitting its
symmetric key and another for the message text itself,and the second option is
just send 1 message containing the text of its message if it
knows (has stored) the symmetric keys of all its neighbors.
THE SKEW APPROACH
The approach is described for hierarchical
WSNs and distributed WSNs.
a)in case of hierarchical WSN:
Here, each sensor node has A unique ID, A pseudo-random function, for generating the next key in sequence, A unique cluster number for each cluster member, and A group key as shared key between all nodes. The node memory is divided into three logical parts:1) RAM memory section, 2) executive code memory section, and
3) non volatile memory section. If an attacker desires to access RAM information, the node detects this and will reset and thus the RAM information will be secure. It is assumed that the data in executive code can be changed.Each node in the hierarchical approach sends an encrypted message by a cluster key. The version in each cluster acts as a sequence number for the next key generation in sequence.The base station node sends a message containing the initial cluster key (Kv1) and the cluster number, encrypted by the group key, to all nodes in each cluster.every key refreshing message has a header(containing informtion about cluster key version and cluster number.) and trailer(containing the message text body) parts. A node on recieving the key refreshing message,
decrypts the message header by the group key and reads the message key version.If the tailor is successfully decrypted, it continues Otherwise, it ignores the message on ground of being insecure or tampered with.
b)case of distributed WSN:
Here each sensor node has: A unique ID, A private key known to the base station too, A pseudo-random function for generating the next key in sequence, A group keyas a shared key between all sensor nodes.all nodes encrypt messages with
group key and the group key can be refreshing
periodically.each individual node which generates new version
group key, broadcasts the group key to all nodes that can receive key refreshing message.
report:
http://nslab.kaist.ac.kr/courses/2009/cs...st/2-4.pdf