How Satellites avoid collisions could have the answer to secure Contact Tracing. No need for GPS or bluetooth

Wifi fingerprints and secure multi party computation could provide an answer.

The signal strength of wifi networks available to your phone is as a fingerprint for where you are. Source: screenshot from wigle.net

Ever wonder how satellites avoid each other? No spy program wants to give up the secret locations of where their satellites will be. The NSA will be real mad if you crash your commercial satellite into theirs. Countries manage to keep their satellites from colliding with maths.

The short answer is multi party computation. Let’s look at a simple example. Say I want to get Chris, Mary and Neil to help me do the computation 10 x 10 but I don’t want them to know what the answer is.

So I write the numbers 3, 2 and 5 down on pieces of paper. I give Chris the number 3, Mary the number 2 and Neil the number 5. I then tell each of them to multiply the number I gave them by 10, write it down and give the result back to me. I can then add them up to get the answer.

The author created the animation to explain MPC.

This is a basically multi party computation. With some fancy maths, this can be used to determine if two users were in the same space…