Industry Insights

Massive Speed Improvement for Encrypted Trilateration

2020-10-31  |  3 min read 

A frequent challenge in radio frequency (RF) applications is finding the location of some object or device. One common method for doing this is called trilateration, and trilateration locates objects using time-based measurements from sensors as various locations. Unlike triangulation, which relies on precise angle measurements, trilateration uses the time information to calculate distances. It then uses those distances as the radii of circles centered on the sensors (S1, S2, and S3 below)) and finds the intersection of all the circles in the "Venn diagram" thus drawn.

In some circumstances, the nature of the application may be such that the sensors cannot know where the other sensors are located. Also, security considerations may prevent the use of unencrypted data to prevent eavesdropping, spoofing, or man in the middle attacks. In such cases, the data is encrypted. Unfortunately, the nature of circles makes encrypted trilateration very slow, often too slow for many practical purposes.

One interesting solution has been developed by Dr. Yasser Shoukry of the University of California at Irvine. Dr. Shoukry and his colleagues found that by approximating the circles as regular polygons, the algorithm can proceed more quickly, in one case changing the time from 11.7 hours to 103 ms. 

This represents a speed improvement on the order of 400,000x, but there is a small penalty to pay in terms of location accuracy. Overall, this is a significant contribution to IoT cybersecurity, which is a complex field that includes a huge attack surface and a rapidly evolving threat landscape. IoT network administrators should apply a variety of cybersecurity tools and make sure to keep current with an application and threat intelligence subscription to ensure that they are not caught off guard.