The Mirror Code

The Resistance, with patience and guile, communicated only through a secret symbolic code, made unbreakable because of the need to use a mirror to make sense of it. After several decades of quietly accepting the tyrannical rule of the state, this evening would mark the beginning of the revolution.

Their simulators had predicted a zero percent chance of failure. Unfortunately, the Authority were waiting for them. It didn't make sense. The plan had been broken down into small pieces and nobody knew enough to betray them.

It was only later that they learned about the hidden cameras inside the mirrors.