Hedy Lamarr Communication Demo
Secure wireless messaging through synchronized channel switching
A live demonstration that shows how shared timing and a secret key can protect wireless messages by rapidly switching channels, making interference far less effective.
Workshop Overview
Students explore secure wireless communication through a hands-on model inspired by an idea associated with Hedy Lamarr. The focus is coordination: when two parties follow the same keyed schedule, the message remains readable for the intended receiver while disruption becomes significantly harder.
Conceptual Framework
The core concept is synchronized channel switching. A sender and receiver follow an identical, key-defined sequence of channel choices. Because both sides change together, the receiver stays aligned with the signal. A disruptor without the key cannot reliably anticipate where the next symbol will appear.
Workshop Structure
1) Brief Setup
The facilitator introduces interference in wireless communication and explains how coordination through a shared key creates a moving target for a jammer.
2) Live Demonstration (about 30–40 minutes)
Two volunteers run a simple digital simulation on a phone or laptop. One plays the receiver and is given the correct 7-bit key. The other plays the jammer and works without the key or with an incorrect guess.
As the simulation runs, the receiver reconstructs a short bitstream by collecting symbols from black-and-white cards distributed throughout the audience, while the jammer attempts to interfere with the stream. The decoded output illustrates how synchronization supports communication even when an attacker is present.
Educational Objectives
By the end of the workshop, students will be able to:
- Describe how a shared key coordinates switching patterns between a sender and receiver
- Explain why loss of alignment makes disruption and interception harder
- Connect the activity to real wireless systems and foundational ideas in security
Setting
High school gymnasium (or a large classroom)
Participants
One large group of student observers (e.g., about 128), plus two volunteers for the live roles
Format
Interactive explanation, live simulation, and audience participation