1. Electric-Field-Based Routing: Secure Spatially Disjoint Routes in MANETs
DARPA Proposer’s Day for
Defense Against Cyber Attacks on Mobile Ad Hoc Networks
An-I (Andy) Wang
Florida State University
Hello, everyone, I’m Andy Wang from the Florida State University. I’m going to tell you about the electric-field-based routing, an innovative way to form secure spatially disjoint routes in mobile ad hoc networks.

2. Goal Defend pair-wise communication channels in MANETs
Electric-Field-Based Routing (EFR) defends against
Black-hole routers
Man-in-the-middle attacks
Byzantine and geographically localized failures
Service degradation
The goal of EFR is to defend against pair-wise communication channels in MANETs. In particular, EFR is designed to defend against black-hole routers, certain types of man-in-the-middle attacks, Byzantine and geographically localized failures, and service degradation.

3. Electric-Field-Based Routing
With two opposite poles
Locally apply electric-field equations at each node
Globally define spatially disjoint routes for all communicating pairs
No further route coordination
The idea of EFR is inspired by nature’s way of forming electric field lines. The observation is that with two opposite charges, you can easily construct spatially disjoint lines along the electric field lines. In the case of networking, we assign the source and the destination with opposite charges, and we can locally apply electric-field equations at each node. And by doing so, we have globally defined spatially disjoint routes for all communicating pairs at all possible positions. And the construction of spatially disjoint routes will require no further route coordination + -

4. Rapid Reconfiguration for Failures and Mobility
One important property of EFR is that it can reconfigure rapidly and constantly for failures and mobility. Suppose you have some tanks. The red tank is the source, and the blue tank is the destination. If you want to talk through EFR, you just simply send out packets at distinct angles and they will reach the destination through disjoint paths. The route memberships are determined at packet arrival times; therefore, each node effectively functions as a switch and does not maintain states regarding its route participation.

5. Rapid Reconfiguration for Failures and Mobility
As a consequence, if you have some helicopters that enters the scene, you can quickly use them to construct disjoint routes. In this case, EFR can statelessly construct 3D spatially disjoint routes.
Stateless 3D routing

6. EFR vs. Black-Hole Routers
STOP
Now let’s see how EFR can handle black hole routers. Suppose one of the nodes is a black-hole router, and you will lose all the packets along that path. However, its surround nodes of the black hole are not affected because the forwarding decision is based on a node’s relative position to the source-destination pair. Therefore, a black hole router cannot claim to be on all field lines for all communication pairs.
Contextual routing

7. EFR vs. Black-Hole Routers
STOP
The destination randomly sends acknowledgements to the source via different routes. After a while, the source will assume failure and find another path
Contextual routing

8. EFR vs. Black-Hole Routers
STOP
Contextual routing

9. EFR vs. Localized Failures
Now, let’s see how EFR can handle localized failures. Suppose a region of node fails simultaneously, possibly due to a bomb. This geographically localized failure is unlikely to break all disjoiint paths, since electric field lines are spatially disjoint.
Spatially disjoint
routes

10. EFR vs. Localized Failures
Spatially disjoint
routes

11. EFR vs. Localized Failures
After a timeout period, the source will find alternative route to recover the broken route.
Spatially disjoint
routes

12. EFR vs. Integrity Breaches
To handle integrity breaches, the source can send duplicate information over disjoint routes. If a node compromises a route, the destination can easily detect the integrity breaches
Redundant routes
and information

13. EFR vs. Integrity Breaches
Redundant routes
and information

14. EFR vs. Multiple Interceptions
STOP
To prevent interceptions, we need encryption. To survive multiple failures, we can apply threshold-based encryption on top of threshold-based encoding. In this case, we have 5 choose 3 encoding, where any three surviving paths can reconstruct the original encrypted message.
STOP
Threshold-based
encryption + encoding

15. EFR vs. Multiple Interceptions
STOP
In this case, we have two intercepted paths, but we can still reconstruct the original encrypted message through the remaining three paths.
STOP
Threshold-based
encryption + encoding

16. Research Challenges Evaluate EFR under different attacks
Overcome practical deployment constraints
Build obstacle/corridor conforming routes
Balance energy consumptions
Explore other stateless approaches of constructing secure spatially disjoint routes
We still need to to quantify EFR’s performance characteristics in terms of security, under various types of attacks. Also, to be deployable, ideally EFR can construct spatially disjoint routes that can conform to physical obstacles and corridors. Currently, we are exploring ways to compute the local center of mass at each node to shape the electric-field lines. Of course, there are other extensions to better cope with the wireless environment. For example, we can adapt wear-leveling to lengthen the battery life of each node. We also want to explore other stateless approaches of constructing secure spatially disjoint routes.

17. Electric-Field-Based Routing
Questions
Electric-Field-Based Routing
An-I (Andy) Wang

18. How to select the next hop
min()
min(D)
Next hop
Field line
Current node
Ideal next hop
Transmission range