1. A Survey of Secure Wireless Ad Hoc Routing
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A Survey of Secure Wireless Ad Hoc Routing
Authors: Yih-Chun Hu and Adrian Perrig
Publish: IEEE Security and Privacy special issue on Making Wireless Work, 2(3):28-39, 2004
Presenter: Danzhou Liu
Dr. Wei CSE, UNSW

2. Contents Introduction Attacks on Ad Hoc Network
Secure Routing in Ad Hoc Network
Discussions
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3. Introduction
This paper is a survey of research in secure ad hoc routing protocols and the challenges faced.
Ad hoc network
Collection of mobile nodes forming a network
Do not have a pre-established network infrastructure such as base access points
Each node moves dynamically and arbitrarily
All nodes typically operate on a common frequency band
Routing protocols are needed if network span exceeds radio range (multi-hop)
Applications
Search and Rescue
Disaster Recovery
Automated Battlefields
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4. Introduction Challenges in ad hoc networks Limited physical security
Lack of infrastructure and authorization facilities
Security protocols for wired networks cannot work for ad hoc networks
Volatile network topology makes it hard to detect malicious nodes
Intrinsic mutual trust vulnerable to attacks
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5. MANET Routing Protocols Classification
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6. DSR
The Dynamic Source Routing (DSR) is a reactive topology-based routing protocol.
Route discovery
When the source node S wants to send a packet to the destination node D, it first consults its route cache. If an unexpired route is found, use this route. Otherwise, S initiates route discovery by broadcasting a route request (RREQ) packet (SID, DID, seq_no).
Each node appends its own identifier when forwarding RREQ
Limited flooding: the node only forwards the RREQ to its neighbors if the RREQ has not yet been seen by the node and if the node’s address does not already appear in the route record.
After receiving RREQ, node D or an intermediate node containing unexpired route to node D generates a route reply (RREP) to node S.
Route maintenance
Route error packets and acknowledgments
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7. DSR: Route Discovery N2 N5 N8 N1 N4 N7 N3 N6 2/24/2019 CDA6938
Destination N1 N5 N8
Source N1
N1-N2-N5
N1-N3-N4-N7
N1-N3-N4 N4 N7 N1
N1-N3-N4
N1-N3
N1-N3-N4-N6 N3
N1-N3-N4 N6
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8. DSR: Route Reply N2 N5 N8 N1 N4 N7 N3 N6 Destination Source 2/24/2019
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9. DSDV
The Destination-Sequenced Distance-Vector (DSDV) is a proactive topology-based routing protocol.
Each node maintains a routing table which stores
next hop towards each destination
a cost metric for the path to each destination
a destination sequence number that is created by the destination itself
Sequence numbers used to avoid formation of loops
Each node periodically and triggeredly forwards the routing table to its neighbors
Route Selection
Select route with higher destination sequence number (This ensure to use always newest information from destination)
Select the route with better metric when sequence numbers are equal.
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10. DSDV: Route Update A B C B increases Seq. No from 100 => 102
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B increases Seq. No from 100 => 102
B sends routing update to A and C
(A, 1, A-500)
(B, 0, B-102)
(C, 1, C-588)
(A, 1, A-500)
(B, 0, B-102)
(C, 1, C-588) A B C
Dest.
Next
Metric
Seq. A
A-550 B 1
B-100 C 2
C-586
Dest.
Next
Metric
Seq. A 1
A-550 B
B-100 C 2
C-588
Dest.
Next
Metric
Seq. A B 1
A-550 2
B-100 C
C-588
B-102
B-102
B-102 2 1 1
C-588
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Dr. Wei CSE, UNSW

11. Contents Introduction Attacks on Ad Hoc Network
Secure Routing in Ad Hoc Network
Discussions
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12. Two Attack Categories (DoS)
Routing-disruption attacks: drive packets onto dysfunctional routes
Routing loop: send forged routing packets to create a routing loop
Black hole: drop all packets
Gray hole: drop some packets, e.g., just forward routing packets but not data packets
Gratuitous detour: claim falsely longer route by adding virtual nodes
Wormhole: use a pair of attacker nodes linked via a private network connection, prevent other nodes to discover routes.
Rushing: fire ROUTE REQUESTS in advance to suppress any later legitimate ROUTE REQUESTS against on-demand routing protocols
Resource-consumption attacks: inject packets into the network
Consume network resources such as bandwidth, nodes’ memory and computation power
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13. Attacker Model Passive Attacker: not inject packets, just eavesdrop
Just threat against communication privacy or anonymity
Not against the network’s function or routing protocol
Not be discussed further
Active Attacker: eavesdrop and inject packets
Assume that the attacker owns all the cryptographic key information of compromised nodes and distributes it among all its nodes.
Active-n-m, where n is the number of nodes it has compromised and m is the number of nodes it owns:
Active-0-1
Active-0-x
Active-1-x
Active-y-x
ActiveVC: controls all traffic between nodes
Increasing strength
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14. Contents Introduction Attacks on Ad Hoc Network
Secure Routing in Ad Hoc Network
Discussions
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15. Key Setup in Ad Hoc Network
How to spread key for authentication.
Secrete Key: a shared key to encode and decode (DEC).
Public Key: a shared public key to encode and a private key to decode (RSA).
Common set of authorities
Protect private key distribution from eavesdrop
Protect legal nodes list distribution from active attack by side channel
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16. Protect Key Distribution
SUCV Addresses
Each node generates a public- and private-key pair
Choose its address based on a cryptographic hash function of the public key
Certificate Authority (CA).
Node has a certificate containing its address, public key and a signature from CA.
CA is vulnerable to compromise. This is overcome by requiring a node to have certificates from several CAs.
Transitive Trust and PGP Trust Graph
Each node signs certificates for other nodes
If A trusts B, and B trusts C, then A trusts C
Public Key Revocation
Revoke the certificate for a compromised node’s public key
Sign Negative certificates
Blacklisting or flooding other revocation information
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17. Ariadne: A Secure On-Demand Routing Protocol for Ad Hoc Network
Ariadne is a secure on-demand routing protocol
Based on Dynamic Source Routing (DSR) Protocol
Withstand node compromise, avoid routing misbehavior by monitoring nodes’ prior performance
Rely only on highly efficient symmetric cryptography
Use one way hashing to overcome node removal from the node list
Route request authenticity & Route reply authentication
Ariadne can authenticate routing messages using one of three schemes:
Shared secrets between each pair of nodes
Shared secrets between communicating nodes combined with broadcast authentication
Digital Signatures
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18. Route Discovery Route Request
<Route Request, initiator, target, id, time interval, hash chain, node list, MAC list> (Note: MAC: Message Authentication Code)
Initiator initializes hash chain to MACKSD(initiator, target, id, time interval)
Non-target node A which receives the request checks <initiator, id> and checks time interval
Time interval : must not be too far in the future and key corresponding to it must not be disclosed yet
If any condition fails, discard the request
If all conditions hold, A appends its address to node list, replaces hash chain with H[A, hash chain], appends MAC of entire Request with TESLA key KAi to MAC list
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19. Route Discovery Route Reply Target checks validity of Request
By determining that the keys are not disclosed yet and that the hash chain is equal to
If Request is valid, target returns a Route Reply
Route Reply
<Route Reply, target, initiator, time interval, node list, MAC list, target MAC, key list>
Sent to initiator along the route in node list
Forwarding node waits and appends its key
Initiator verifies each key in key list, target MAC, each MAC in MAC list
H[nn, H[nn-1, H[…,H[n1, MACKSD(initiator, target, id, interval)]…]
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20. Route Discovery Route Request
RS* = <M, h0, (), ()>
RA* = <M, h1, (A), (MA)>
RB* = <M, h2, (A, B), (MA, MB)>
RE* = <M, h’2, (A, E), (MA, ME)>
Route Request
Route to be found: S  A  B  C  D
M = Request, S, D, id, ti
S : h0 = MACKSD(M)
S   : M, h0, (), ()
A : h1 = H (A, h0)
MA = MACKAti M, h1, (A), ()
A   : M, h1, (A), (MA)
B : h2 = H (B, h1)
MB = MACKBti M, h1, (A, B), (MA)
B   : M, h2, (A, B), (MA, MB)
C : h3 = H (C, h2)
MC = MACKCti M, h3, (A, B, C), (MA, MB)
C   : M, h3, (A, B, C), (MA, MB, MC) S
RA*
RS*
RE* E A
RB* B
RC*
RF* F C
RG* G D
Finally, D checks validity of request by checking whether keys are disclosed, and hash chain consistent
RC* = <M, h3, (A, B, C), (MA, MB, MC)>
RF* = <M, h’3, (A, B, F), (MA, MB, MF)>
RG* = <M, h’4, (A, B, C, G), (MA, MB, MC, MG)>
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21. Route Discovery Route Reply
M = Reply, D, S, ti , (A, B, C), (MA, MB, MC) 
D : MD = MACKDS (M)
D  C : M, MD, ()
C  B : M, MD, (KCti)
B  A : M, MD, (KCti, KBti)
A  S : M, MD, (KCti, KBti, KAti)
RDC = <M, MD, ()>
RCB = <M, MD, (KCti)>
RBA = <M, MD, (KCti, KBti)>
RAS = <M, MD, (KCti, KBti, KAti)> S
RAS E A
RBA B
RCB F
Finally, S verifies each key in key list, target MAC, each MAC in MAC list C
RDC G D
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22. SEAD: Secure Efficient Ad Hoc Distance Vector
Based on DSDV (Destination-Sequenced Distance-Vector) ad hoc routing protocol
Overcomes attackers creating incorrect routing state
Using one-way hashing chain and sequence number
Authenticating Routing Updates
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23. Secure AODV (Ad Hoc On-demand Distance Vector) Routing Protocol
ARAN: Authenticated Routing for Ad Hoc Networks
Each node has a certificate signed by a trusted authority
On-Demand Routing with route discovery and maintenance
Record next hop and when unavailable it initiate route maintenance
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24. Secure AODV SAODV Add signature extensions to AODV
Use hash chain to confirm each hop
Allow a route reply double signature extension (RREP-DSE) from intermediate node.
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25. Secure Link-State Routing
Digital signatures and one way hash chains
Updates through the Neighbor Lookup Protocol (NLP)
Hash chains used to authenticate hop count
Limited hops when LS update
Lightweight flooding prevention
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26. Reputation Based Systems
Require underlying secure routing protocol
Four components of Confidant: monitor, trust monitor, reputation system, and path manager.
Using Weight list
List of links with cost metric associated with each link
Protect route from existing attacker
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27. Discussions Strengths of the paper Weaknesses of the paper Future work
Discuss possible attacks
Presents an attacker model
Presents state-of-art secure wireless ad hoc routing techniques
Weaknesses of the paper
A more complete model of possible attacks would let the protocol designers evaluate the security of their routing protocols.
Not discuss how to improve performance efficiency
Future work
Model secure routing problems
Design routing protocols that have strong security as well as good performance
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28. Thank You
Q&A
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