Quantum Key Distribution using BB84

In this video you will learn what quantum key distribution (QKD) is and how it works. Listen to Tim Coopmans talk about QKD and its most famous protocol BB84.

To understand how the protocol works it is essential to know the 3 basic basis of a Qubit in the Bloch sphere (Z, X, Y) and what impact does it have to take a measurement in a certain state that might be in a superposition. Tim will brush on these concepts first and jump to the BB84 protocol later on to unleash the true power of quantum communication.

This was one of the first ideas for quantum communication that was developed. From there a new field of investagation arose trying to find out what could be done using similar schematics. BB84 can be extended using 6 states (including now the Y basis) instead of 4. We can also reproduce a similar protocol but using now entangled particles, named E91.

Another concern of the field is real implementation of such protocols and how they might be affected when things are placed down on earth: detection failure, missalignment of polarization, loss of information and depolarization... Many implementations of qubits (mainly photons with different information encoding systems) are under investigation nowadays to overcome certain vulnerabilities of real systems: polarization, energy-time entanglement...

Are you wondering who Alice and Bob are? Are you not familiar with the one-time-pad protocol yet? If you want to understand better what problems QKD is trying to solve don't hesitate and watch the related videos on classical ways of secure communication such as the one-time-pad.