Securing Vehicular Commuinications

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Securing Vehicular Commuinications Assumptions,
Requirements, and Principles

• P. Papadimitratos, EPFL, Lausanne, Switzerland
• V. Gligor, University of Maryland, College Park,
  USA
• J-P. hubaux, EPFL, Lausanne, Switzerland
• Presentor Guo Yu Lu

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Outline

• Introduction
• Security Requirements
• System Model
• Communication Model
• Adversary Model
• Design Principles

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What is VANET ?
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What is VANET

• Vehicular AdHoc Network, or VANET
• a form of Mobile ad-hoc network
• provide communication
• - among nearby vehicles
• - between vehicles
• - nearby fixed equipment

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Introduction

• How vehicular communications work
• - road-side infrastructure units (RSUs),
• named network nodes, are equipped
• with on-board processing and wireless
  
• communication modules

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How vehicular communications work (Continue)

• - vehicle-to-vehicle (V2V) and
  vehicle-to-infrastructure
• (V2I) communication will be possible

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What can VANET provide ?
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Warnings!!!

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Warnings!!!
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traffic and road conditions
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traffic and road conditions
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What can VANET provide

• The VANET can provide
• Safety
• Efficiency
• Traffic and road conditions
• Road signal alarm
• Local information

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Related work

• Research have been worked
• Outline challenges for VANET
• - availablility, mobility
• Describe particular attacks
• -DoS, alteration attacks
• Suggest solution towards attacks
• This paper provide a basis for the development
• of future vehicular security schemes

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• Security Requirements

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SECURITY
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Security Requirements

1. Message Authentication and Integrity
2. Message Non-Repudiation
3. Entity Authentication
4. Access Control Authorization
5. Message Confidentiality
6. Privacy and Anonymity
7. Availability
8. Liability Identification

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Security Requirements

• Message Authentication and Integrity
• - Message must be protected from any
• alteration
• Message Non-Repudiation
• - The sender of a message cannot deny
  having sent a
• message
• Entity Authentication
• - The receiver is ensured that the
  sender generated a
• message
• - The receiver has evidence of the
  liveness of the sender

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Security Requirements

• Access Control
• -determined locally by policies
• - authorization established what each
• node is allowed to do in the network
• Message Confidentiality
• - the content of a message is kept
• secret from those nodes that are not
• authorized to access it

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Security Requirements

• Privacy and Anonymity
• - vehicular communication (VC)
• systems should not disclose
• any personal and private
• information of their users
• - any observers should not know any future
• actions of other nodes
• - anonymity may not be a reasonable
  requirement
• for all entities of the vehicular
  communications
• system

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Security Requirements

• Availability
• - protocols and services should remain
• operational even in the presence of
• faults, malicious or benign
• Liability Identification
• - users of vehicles are liable for their
  deliberate or
• accidental actions that disrupt the
  operation of other
• nodes

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• System Model

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System Model

• Vehicular communications system
• - Users
• - Network nodes
• - Authorities

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System Model
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System Model

• Users
• - user is the owner or the
• driver or a passenger
• of the vehicle
• Network Nodes
• - processes running on computing
  platforms
• capable of wireless communication
• - Mounted on vehicles and road-side units
  
• (RSUs)

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System Model

• Authorities
• - public agencies or
• corporations with
• administrative powers
• - for example, city or state
• transportation authorities

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System Model

• VC system operational assumptions
• Authorities
• Vehicle Identification and Credentials
• Infrastructure Identification and Credentials
• User Identification and Credentials
• User and Vehicle Association
• Trusted Components

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System Model

• Authorities
• - trusted entities or nodes
• - issuing and manage identities and
• credentials for vehicular network
• - establish two-way communication with
  nodes
• Vehicle Identification and Credentials
• - unique identity V
• - a pair of private and public keys, kv
  and KV
• - certificate CertXKV, AV issued by
• authority X
• - V denotes on-board central
• processing and communication
• module

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System Model

• Note. From Securing Vehicular Communications
  Assumptions, Requirements, and Principles, by P.
  Papadimitratos, V. Gligor, J-P Hubaux, In
  Proceedings of the Workshop on Embedded Security
  in Cars (ESCAR) 2006, November 2006.

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System Model

• Infrastructure Identification and Credentials
• - unique identity I
• - a pair of private and public key kI and
  KI
• - certificate CertZKI, AI issued by
  authority Z
• - gateway to the authorities
• - gateway to the mobile vehicles
• - RSUs locations are fixed
• - public vehicles
• -considered trustworthy
• -be used to assist security
• related operations

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• What are public vehicles ?

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System Model

• User identification and Credentials
• - Unique identity, U
• - a pair of private and public keys, kU
  and KU
• - Certificate CertYKU , AU issued by
  authority Y
• User and Vehicle Association
• - user is the owner or the driver or a
• passenger of the vehicle
• - assume only one user can operate
• a vehicle
• - assume the user is the driver

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System Model

• Trusted Components (TCs)
• - nodes equipped with trusted
  components, i.e., built-in
• hardware and firmware
• - TCs enforce a policy on the
  interaction with
• the on-board software
• - Access to any information stored in
  the TCs and
• modification of their functionality
  can be done only
• by the interface provided by the TCs.
  
• - perform cryptographic operations with
  signature
• generations and verifications

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• Communication Model

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Communication Model

• Model the wireless communication in vehicular
  networks, whose connectivity can change
  frequently
• Focus mainly on the data link layer

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Communication Model

• Data-link layer primitives and assumption
• SendL(V,m) transmits message m to node V within
  
• radius R of the
  transmitting node
• BcastL(m) broadcasts message m to all nodes
• within radius R of the
  transmitting node
• ReceiveL(m) receives message m transmitted by a
  
• node within radius R of
  the receiver
• A link (W,V) exists when
  two nodes W and
• V are able
  to communicate directly

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Communication Model

• Links are either up or down, and their state does
  not change faster than the transmission time of a
  single packet
• The network
  connectivity, at a particular
• instance in time.
  Modeled as the graph G
• the edges of which are
  all up links.
• Transmissions from W are received by all nodes V
  such that (W, Vi) is up during the entire
  duration of the packet transmission
• Packets are delivered
  across an up link
• within a maximum link
  delay t or they are
• not delivered at all.

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Communication Model

• Communication across the network is dependent on
• availability of sufficient resources
• bandwidth
• - shared medium contend
• - bandwidth can fluctuate
• - unevenly distributed
  among neighbors
• - links may be congested

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Communication Model

• Communication Radius, R
• Vary over time
• Different classes of nodes may operate with
  different R
• Multi-domain and Highly Volatile environment
• Nodes are not bound to administrative and
  geographical boundaries
• Any two or more nodes communicate independently

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Communication Model

• Frequent Broadcast Communication
• Most of the vehicular network traffic is
  Broadcasted at the network or application layers
• Message are transmitted either
• periodically or triggered by network events
• Transmission period is low
• Time-sensitive Communication
• Message delivery can be constrained by deadlines
• - different messages have different
  delay requirements

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• Adversary Model

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Adversary Model

• Network nodes
• - correct or benign
• - faulty or adversaries
• - external adversaries
• - Internal adversaries
• - active adversaries
• - passive adversaries

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faulty is not always malicious!!!
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Adversary Model

• Internal Active Adversaries
• Multiple adversarial nodes
• - adversaries are
• independent
• - adversaries can collude
• - based on TCs, colluding
• adversaries are
• prevented from exchanging
• cryptographic material and
• credentials

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Adversary Model

• Internal Active Adversaries (continue)
• non-adaptive adversary ? Adversarial nodes are
  fixed
• adaptive adversary ? Adversarial nodes change
  over time
• Computationally bounded adversary
• ? adversaries are computationally limited
• - limited resources and
  computational power
• - the knowledge of an adversary
  is limited
• - memory finite

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Design Principles

• Default Network Access
• Locality and Timeliness as Privileges
• Visibility of Events
• Mandated (non-circumventable) Mediation
• Accountability
• Vehicle Autonomy
• Separation of Privilege
• Non-frameability
• Stage Response to Faulty Behavior
• Reconfigurability
• Privacy Conservation
• Usability

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• Questions / Comments