This document presents an overview of Vehicular Ad-Hoc Networks (VANETs). It discusses the system model, including network nodes like vehicles and roadside infrastructure that communicate. The communication model describes frequent broadcast communication between nearby nodes. Security requirements are outlined, such as message authentication, non-repudiation, and privacy. The adversary model considers both external and internal active and passive attackers. Design principles for VANET security are also presented, including accountability, separation of privilege, and privacy conservation.

1. VANET
Presentor: Ramu

2. Outline
 Introduction
 Security Requirements
 System Model
 Communication Model
 Adversary Model
 Design Principles

3. What is VANET ?

5. What is VANET
Vehicular Ad–Hoc Network, or VANET
 a form of Mobile ad-hoc network
 provide communication
- among nearby vehicles
- between vehicles
- nearby fixed equipment

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

7. How vehicular communications work
(Continue)
- vehicle-to-vehicle (V2V) and vehicle-to-infrastructure
(V2I) communication will be possible

9. What can VANET provide ?

10. Warnings!!!

11. Warnings!!!

12. traffic and road conditions

13. traffic and road conditions

16. What can VANET provide
The VANET can provide
 Safety
 Efficiency
 Traffic and road conditions
 Road signal alarm
 Local information

17. 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

18. Security Requirements

19. SECURITY

20. 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

21. 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

22. 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

23. 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

24. 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

25. System Model

26. System Model
 Vehicular communications system
- Users
- Network nodes
- Authorities

27. 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.

29. 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)

30. System Model
 Authorities
- public agencies or
corporations with
administrative powers
- for example, city or state
transportation authorities

31. System Model
 VC system operational assumptions
1. Authorities
2. Vehicle Identification and Credentials
3. Infrastructure Identification and Credentials
4. User Identification and Credentials
5. User and Vehicle Association
6. Trusted Components

32. 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 CertX{KV, AV} issued by
authority X
- V denotes on-board central
processing and communication
module

33. 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.

34. System Model
Infrastructure Identification and Credentials
- unique identity I
- a pair of private and public key kI and KI
- certificate CertZ{KI, 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

35. What are public vehicles ?

37. System Model
 User identification and Credentials
- Unique identity, U
- a pair of private and public keys, kU and KU
- Certificate CertY{KU , 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

38. 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

39. Communication Model

40. Communication Model
 Model the wireless communication in
vehicular networks, whose connectivity can
change frequently
 Focus mainly on the data link layer

41. 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

42. 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 τ or they are
not delivered at all.

43. 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

44. 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

45. 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

46. Adversary Model

47. Adversary Model
 Network nodes
- correct or benign
- faulty or adversaries
- external adversaries
- Internal adversaries
- active adversaries
- passive adversaries

48. faulty is not always malicious!!!

49. 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

50. 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

51. 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

52. Questions / Comments