Title: Secure Routing for Mobile Ad hoc Networks
 1Secure Routing for Mobile Ad hoc Networks
Panagiotis Papadimitratos and Zygmunt J.HaasCNDS 
2002
- Present by Jung, jong-kwan
CS710 Special issues in Computer Architecture 
 2Contents
-  Introduction 
-  Related work 
-  Proposed Scheme 
-  Protocol Description 
-  Protocol Correctness Proof 
-  Conclusions
3Introduction
-  Feature of MANET 
- Absence of a fixed infrastructure 
-  - Impede the practice of establishing a line of 
 defense
- Roaming node 
-  - difficult to have a picture of the ad hoc 
 network
-  membership 
- No guarantee that a path between two nodes would 
-  be free of malicious nodes 
-  Technique in the MANET context of route 
-  discovery based on broadcasting query packets 
4Related Work
- Enforcing Service Availability in Mobile Ad Hoc 
- Provide incentive to nodes 
- Ad hoc On-Demand Distance Vector Routing 
- An extension of the AODV 
- Secure Message Transmission in Mobile Ad Hoc 
 Networks
- Determines a set of diverse paths connecting the 
 source and the destination nodes
5Proposed Scheme(1/3)
-  Basic assumption 
- Focus on bi-directional communication between a 
 pair of nodes
- Security Association (SA) 
- Existence of shared key Ks,t 
- An attack mounted by two colluding nodes during a 
 single route discovery
6Proposed Scheme(2/3)
-  Overview 
- Provide approach to the secure route discovery 
 operation
- Source node S initiates the route discovery 
- Intermediate nodes relay route request 
- Destination T constructs the route replies
7Proposed Scheme(3/3)
-  Example Topology 
- Qs,tn1,n2,,nk  SRP Header for a query 
 searching for T
- Rs,t n1,n2,,nk
8Proposed Scheme(1/4)
- Scenarios of security attacks by two malicious 
 nodes
- Scenario 1 
- M1 receives Qs,tS 
- M1 generates Rs,t  S,M1,T 
- T disallows any intermediate node to provide a 
 reply
- M1 does not posses Ks,t
9Proposed Scheme(2/4)
- Scenario 2 
- M1 discards request packets arriving from its 
 neighbors
- Scenario 3 
- M1 receives Rs,t  S, 1, M1, 5, 4, T and relays 
 Rs,t  S, 1, M1, Y, T
- Integrity protection provided by the MAC
10Proposed Scheme(3/4)
- Scenario 4 
- M2 receives Qs,t  S, 2, 3 and relays Qs,t  
 S, X, 3,M2
- Scenario 5 
- M1 attempts to forward Qs,t  S, M  IP 
 spoofing
- Mask its identity will be temporary 
11Proposed Scheme(4/4)
- Scenario 6 
- M1 attempts to return a number of replies with a 
 different spoofed IP
- Relay more than one route requests, placing a 
 different IP address in each of them
12Protocol Description (1/5 )
-  SRP can be incorporated in the underlying basic 
 protocol
01234567890123456789012345678901
IP Header
Basic Routing Protocol Packet
SRP Header 
 13Protocol Description (2/5 )
-  Route Request 
- S maintains a Query Sequence number Qseq 
- S generates a 32-bit random Query Identifiers Qid 
- Both Qid and Qseq are placed in the SRP header
01234567890123456789012345678901
Reserved
Type
Query Identifier
Query Sequence Number
SRP MAC 
 14Protocol Description (3/5 )
- Query Handling/ Propagation 
- Intermediate nodes parse the received Route 
 Request
- If an SRP header is present 
- Extract the Qid, the source and destination 
 address
- Queries with Qid match one of the Query table 
 entries are discarded
- Intermediate nodes measure the frequency of 
 queries received from their neighbors
- Benign node maintains a priority of ranking of 
 its neighbors
- The highest priority  nodes generating request 
 with the lowest rate
15Protocol Description (4/5 )
- Route Reply 
- T validates the received route request packet 
- If Qseq lt Smax, the request is discarded 
- Otherwise. T calculates the keyed hash of the 
 request field
- T generates a number of replies 
- Source-route a reply with an empty payload 
-  Route Reply Validation 
- S check the source and destination address, Qid, 
 Qseq
- S calculates the MAC 
16Protocol Description (5/5 )
-  Intermediate Node Replies 
- Intermediate Node Reply Token(INRT) 
01234567890123456789012345678901
SRP Header
IN Reply Token 
 17Protocol Correctness Proof(1/4)
- Idealized SRP 
- H  Message Authentication Code function 
- Rst  route reply 
(1) Qs,t,H(Qs,t,Ks,t)
S
T
(2) Rs,t,route,H(Rs,t,route,Ks,t) 
 18Protocol Correctness Proof(2/4)
- Initial assumption 
- For message(1), we have
(i)
(ii)
(iii)
(iv) 
 19Protocol Correctness Proof(3/4)
- From (i), (iii), (iv), (vi), we get 
(v)
(vi)
(vii) 
 20Protocol Correctness Proof(4/4)
(viii)
(ix)
(x) 
 21Conclusions
- Proposed an efficient secure routing protocol 
- Guarantees the discovery of correct connectivity 
 information over an unknown network
- The resultant protocol is capable of operating 
 without the existence of an on-line certification
 authority