2
Outlines
Security primitives in TinySec
Encryption Schemes
Keying mechanism
WMSN
►Architecture
►Applications
►Advantages
►Design Considerations
►Protocols
WSAN
►Motivation
►WSN vs WSAN
►Architecture
►Issues
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Security Primitives & Encryption in WMSN & WSAN, Slides of Wireless Networking
An overview of security primitives, encryption schemes, keying mechanisms, and protocols used in wireless multimedia sensor networks (wmsn) and wireless sensor actor networks (wsan). It covers topics such as message authentication codes (mac), initialization vectors (iv), symmetric key encryption schemes, and cbc mode encryption. The document also discusses the advantages and design considerations of wmsn and wsan, as well as their motivations and differences.
Typology: Slides
2011/2012
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2
Outlines
Security primitives in TinySec
Encryption Schemes
Keying mechanism
WMSN ►^
Architecture ►
Applications ►
Advantages ►
Design Considerations ►
Protocols
WSAN ►^
Motivation ►
WSN vs WSAN ►
Architecture ►
Issues
3
Last Lecture
Transport Protocols for WSN
TCP/UDP for WSN
Protocols ►
PSFQ
ESRT
CODA
Security Threats in WSN
TinySec
Motivations of Link Layer security
5
TINYSEC-DESIGN
2 Security Options- ►
Authentication Encryption ( Tinysec-AE)•
TinySec encrypts the data payload and authenticates thepacket with a MAC.
-^
The MAC is computed over the encrypted data and thepacket header.
Authentication only (Tinysec-Au)•
TinySec authenticates the entire packet with a MAC, but thedata payload is not encrypted.
Encryption : semantically secure encryptiontypically requires two design decisions ►
Specifying the IV format
Selecting an encryption Scheme
6
Tinysec IV format
IV too long- add unnecessary bits to the packet
Too short – Risk of repetition
How long should be the IV? N bit IV repeat after 2^n+1. ►^
If we use a n bit counter repetitions will not happen before thatpoint. ►
Pseudorandom would repeat with probability of 2^(n/2)
Active message handler type
Destination
8
CBC
IV is XOR'ed with the first data block before it is encrypted.
Feed the result of encryption back into the encryption of the nextblock.
The plain-text is XOR'ed with the previous cipher-text block beforeit is encrypted.
The encryption of each block depends on all the previous blocks.
This requires that the decryption side processes all encryptedblocks sequentially
An error in an encrypted block ►^
causes the block with the error to be completely garbled. ►
The subsequent block will have bit errors at the same positions as theoriginal erroneous block. ►
The blocks following the second block will not be affected by the error.Hence, CBC is self-recovering
9
Keying mechanism
Use per-link keying, ►^
separate Tinysec key for each pair of node wishing tocommunicate. ►
Drawback: Key distribution becomes a challenge.
Allow a group of nodes to share a TinySec key ratherthan each pairs. ►^
Group keying provides an intermediate level of resilience.
Appropriate keying mechanism for a particular networkdepends on several factors.
Tinysec key- A pair of skipjack key-one forauthentication, one or encryption.
Simplest keying mechanism: ►^
Use a single key for the entire network, Preload the key beforedeployment.-Adversary can compromise on node and get thekey..
11
Reference Architecture of WMSN
12
New Applications
Storage and Retrieval of Interesting Activities- e.g.,IrisNet[93]. (2004)
Traffic congestion avoidance, traffic. enforcementand control systems.
Smart parking advice system. (2005)
Automated Assistance for the elderly and familymonitors. (2005)
Manufacturing process control for semiconductorchip, food or pharmaceutical products.
14
Design Considerations
Application-specific QoS requirements ►^
Snapshot and Streaming multimedia ►
Flexible architecture to support heterogeneous applications
Multimedia source coding ►^
intra-frame/inter-frame ►
distributed source coding
Multimedia in-network processing
Multimedia coverage model development
Power consumption
15
Examples of Deployed WMSN
SensEye ►^
Three tasks: object detection, recognition
and tracking. ►
Objective: Demonstrate a camera sensor
network containingheterogeneous elementsprovides numerous benefitsover traditionalhomogeneous sensornetworks.
17
Traffic Management and Admission
Control
Tasks: ►^
Prevent applications from establishing data flows when the networkresources needed are not available ►
Traffic classes - provide differentiated service between real-time anddelay-tolerant applications, and loss-tolerant and loss-intolerantapplications.
Related work: ►^
An application admission control algorithm is proposed whoseobjective is to maximize the network lifetime subject to bandwidth andreliability constraints.(2003) ►
An application admission control method is proposed to determineadmissions based on the added energy load and application rewards.(2003)
18
Transport Layer
TCP or UDP? ►
For real-time applications like streaming media, UDPseems preferred over TCP
Effect of dropping packets in UDP
Support for traffic heterogeneity
TCP with appropriate modifications ispreferable over UDP for WMSNs, ifstandardized protocols are to be used.
20
Using Multiple Paths
Regulating streaming through multiple TCP connections. (2005) ►^
Sender sends the desired streaming rate and allows throughputreduction to the receiver. ►
Receiver measures the actual throughput, controls the rate within theallowed bounds by using multiple TCP connections and dynamicallychanging its TCP window size for each connection.
Spliting a large burst of data into several smaller bursts ►^
Multi-flow Real-time Transport Protocol (MRTP). (2006)
Allows the sink to regulate multiple sources associated with asingle event ►^
COngestion Detection and Avoidance (CODA) protocol. (2003)
21
WSAN
I. Motivations
Environmental Applications ►^
Detecting and extinguishingforest fire
Distributed Robotics & SensorNetworks ►^
Mobile robots dispersedthroughout the field in sensornetworks, e.g. minesdetection and destruction.