SPINS: Security Protocols for Sensor Networks
Master’s Degree 29th Park. Joon-young
Contents• Introduction
• System Assumptions
• Requirements for Sensor Network Security
• SNEP / Counter Exchanging / µTESLA
• Implementation
• Evaluation
• Question & Answer
Introduction
Limited Processing Power
Limited Storage
Low Bandwidth
Inefficient Energy
Sensors will have..
SPINS
Data Confidentiality !
Two-party Data Authentication !
Integrity !
Evidence of Data Freshness
Authenticated Broadcast for Resource-constrained
Environments
SNEP µTESLA
System Assumptions
BaseStation
Communication arch.
Node
e.g., sensor readings
Base Station
NodeBaseStation
Communication arch.
e.g., specific requests
Node
NodeBaseStation NodeNode
Communication arch.
e.g., routing beacons, queries, reprogramming..
Node
Node
Node
Other assumptions
Communication arch.
Trust requirements Design guidelines
Requirements
WEAK? !
STRONG?
Data Confidentiality
Data Authentication
Data Integrity
SNEP(with weak freshness)
Semantic security
Data authentication
Replay protection
Low communication overhead
FreshnessFreshness
SNEP(with strong freshness)
Freshness
send nonce
Counter exchanging
Bootstrapping Counter
Re-synchronizing Counter
nonce
TESLA
Efficient Authenticated Broadcast Protocol
TESLA
NOT APPL
ICABLE
uses Digital Signature
uses Big Packet Size
TESLA
uses Symmetric mechanisms
discloses the key 1/epch
µTESLA
Base Station
- Sender Setup
…, , , ,
one-way func.
…
µTESLA
Base Station
- Broadcasting Auth.
…, , ,
Nodes
µTESLA
Base Station
- Broadcasting Auth.
…, , ,
Nodes
µTESLA
Base Station
…, , ,
Nodes
- Bootstrapping New Receiver
Hi
µTESLA
Base Station
…, , ,
Nodes
- Authenticating broadcast packets
µTESLA
Fake Station Nodes
- Authenticating broadcast packets
Implementation
• subset of RC5
• CTR Encryption Function
• used Nonce
• use MAC for PRG
• compute MAC per packet
Evaluation
Code Size
Performance
Evaluation
Ram requirements
Energy costs