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