1. A Survey of Secure Wireless Ad Hoc Routing
Article by: YIH-CHUN HU, ADRIAN PERRIG
IEEE Security and Privacy special issue on Making Wireless Work, 2(3):28-39,  2004.
Presented by: Devendra Salvi

2. Multihop Ad Hoc network
Access Point
Ad Hoc N/W
Network boundary

3. Outline Attacks on Ad hoc networks Key setup in Ad hoc networks
SEAD in mobile wireless Ad Hoc network
A secure on-demand routing protocol for ad hoc networks
Securing AODV
Review
Questions

4. Attacks on Ad hoc networks
Attacks on ad hoc network routing protocols are mainly
Routing disruption attack
Wherein the attacker causes legitimate data packets to be routed in dysfunctional ways.
Resource consumption attack
Wherein the attacker injects packets into the network to consume network resources such as bandwidth or to consume node resources such as memory/computational power.

5. Attacks on ad hoc network routing protocols
Shortest path
Routing disruption attack
Drop packets
Blackhole / Grayhole
Source
Destination
Insert forged routing packets

6. Attacks on ad hoc network routing protocols
Wormhole
Records Traffic for network A & replays it in network B
Intruder Node X
Node A
Node B
Intruder Node X’
X’mission range of B
X’mission range of A

7. Attacks on ad hoc network routing protocols
Solution for wormhole attacks
Packet Leashes is keeping constraints on packet in either of two ways
Temporal
Temporal leashes rely on extremely precise time synchronization and timestamps in each packet. A packet’s travel time is approximated as the difference between the receive time and the timestamp.
Geographical

8. Attacks on ad hoc network routing protocols
Solution for wormhole attacks
Packet Leashes is keeping constraints on packet in either of two ways
Temporal
Geographical
Where in location information and loosely synchronized clocks is used to create a leash
The distance between the sender and receiver is calculated nodes velocity and timestamps.

9. Key setup in Ad hoc networks
To authenticate a legitimate node
Establishing private keys
Share private keys between each pair of nodes before deployment.
Pitfall: when new nodes join network later
Solution:
1. Establishing trust and keys between two nodes in an ad hoc network; Master-slave nodes.

10. Key setup in Ad hoc networks
SUCV addresses (statistically unique cryptographically verifiable)
Each node generates a public- and private-key pair, and then chooses its address based on a cryptographic hash function of the public key
E.g. 1. A node’s entire IPv6 address is the hash function’s output

11. Key setup in Ad hoc networks
Certificates from a certificate authority
node address, node public key,
and a signature from the CA (s).

12. Key setup in Ad hoc networks
Transitive trust and PGP trust graphs
node address, node public key,
and a signature from the CA.
Node B
Node A
Node C

13. SEAD in mobile wireless Ad Hoc network
To support use of SEAD with nodes of limited CPU processing capability, and to guard against DoS attacks in which an attacker attempts to cause other nodes to consume excess network bandwidth or processing time, efficient one-way hash functions are used while asymmetric cryptographic operations in the protocol are not used.
SEAD: Secure efficient Ad hoc Distance vector routing protocol.

14. SEAD in mobile wireless Ad Hoc network
Destination-Sequenced Distance-Vector ad hoc network routing protocol (DSDV).
Distance vector routing; each router maintains list of all possible destinations within the network.
Each node router entry maintains:
1. address of destination (identity)
2. Nodes which form shortest known distance to destination (metric) usually # of hops.
3. address of nodes neighbor which is the first hop on the shortest route to destination

15. SEAD in mobile wireless Ad Hoc network
Destination-Sequenced Distance-Vector ad hoc network routing protocol (DSDV).
DSDV introduces a sequence number in each routing table entry.
Prevents routing loops.

16. SEAD in mobile wireless Ad Hoc network
Hash Chains
A one-way hash chain is built on a one-way hash function.
To create a one-way hash chain, a node chooses a random x ∈ {0,1}ρ and computes the list of values h0, h1, h2, h3, ..., hn,where h0 = x, and hi = H(hi –1) for 0 < i ≤ n, for some n.
E.g. Given an authenticated hi value, a node can authenticate hi–3 by computing H(H(H(hi –3))) and verifying that the resulting value equals hi

17. A secure on-demand routing protocol for ad hoc networks
Ariadne is a secure on-demand routing protocol that withstands node compromise and relies only on highly efficient symmetric cryptography.
Ariadne discovers routes on-demand (as they are needed) through route discovery and uses them to source route data packets to their destinations.
*Message authentication code (MAC) computed with key KSD over unique data—for example, a timestamp

18. Securing AODV
The Ad hoc On-demand Distance Vector routing protocol (AODV) spreads distance vector routing information in an on-demand manner.
There are two protocols to secure routing protocols
Authenticated routing for ad hoc networks (ARAN)
SAODV

19. Securing AODV Authenticated routing for ad hoc networks (ARAN)
Kimaya Sanzgiri and her colleagues developed authenticated routing for ad hoc networks (ARAN), which is based on AODV.
In ARAN, each node has a certificate signed by a trusted authority, which associates its IP address with a public key.

20. Securing AODV
(ARAN)
1. To initiate a route discovery, the initiator S broadcasts a signed ROUTE REQUEST packet that includes the target D, its certificate (certS), a nonce N, and a timestamp t.
2. Each node that forwards this REQUEST checks the signature or signatures. Node C checks node B’s certificate certB, then checks the signature on the outer message. C then verifies the certificate certS for initiator S and uses the key in the certificate to verify the signature on the REQUEST.
3. If the signatures are valid, the forwarding node removes the last forwarder’s signature and certificate, signs the original REQUEST, and includes its own certificate. The node then broadcasts the REQUEST. Node C removes node B’s signature, signs the resulting REQUEST, and includes its own certificate. Node C then broadcasts the REQUEST.
4. When the first ROUTE REQUEST from a route discovery reaches the target, the target signs a ROUTE REPLY and sends it to the node from which it received the REQUEST. the target D returns a signed ROUTE REPLY to the previous hop C

21. Securing AODV
SAODV:
A signature is used to authenticate most fields of a route request and route reply and hash chains are used to authenticate the hop count.
A node first authenticates the RREQ to ensure that each field is valid.
It then performs duplicate suppression to ensure that it forwards only a single RREQ for each route discovery.
The node then increments the hop-count field in the RREQ header, hashes the hop count authenticator, and rebroadcasts the RREQ, together with its RREQ-SSE extension.

22. Review
Strengths
Comprehensive study of security protocols on wireless ad hoc networks

23. Review
Weaknesses
Authors do not present any evaluations of the protocol.

24. Improvements
Implementation of the discussed protocols.

25. Questions ?