We are going to Court!

Mission 3: The No-Cloning Mystery. Part of the Quantum Courier Service, a free course from the Oxford University Quantum Information Society.

Pack your finest robes, Recruit. We have been summoned to the High Quantum Court in Geneva. The Echo Network’s legal team has just filed a devastating motion. They publicly claim that our entire QCS security architecture is a fraud. They claim they have invented a "Quantum Photocopier"; a machine that can perfectly duplicate any intercepted qubit without measuring or collapsing it.

If they are telling the truth, the global treaty on quantum communication will be shredded. The Echo Network has essentially walked into court claiming they have invented a perpetual motion machine that runs on Earl Grey tea. It is our job to show the judge the hidden power cord. You must prove, using the unbending laws of physics, that perfectly copying an unknown quantum state is impossible.