A tale of Santa Claus in a quantum world

When quantum long-term security saves the magic

Damien, a young boy, received a big gift for Christmas: a wonderful computer! He decided to plug in all the cables, and to boot in the famous software: Windows 95!

It was marvellous! The new games were just crazy! And the quality of visuals! It was a very good computer.

A few weeks later, Damien enabled system files visibility, to tweak a little his OS. He discovered a hidden file, in the root of the C: hard drive. It was an encrypted message! And it seemed to be very difficult to decrypt, close to impossible in fact!

Many years later, Damien forgot this file and bought a new computer, but he still kept all his old electronic equipment. Later, he decided to study computer science and electronic engineering.

He finally received his bachelor’s degree and decided to crack this message. He had studied cryptography and tried many algorithms, until one day he finally succeeded in cracking this DES-encrypted message.

Inside, Damien could read: « I exist! But if you manage to decipher this message, I will disappear and you will never see me again… Santa Claus ».

Damien knew that Santa Claus would never bring him Christmas’ gifts again. To not inflict this punishment onto other children, and after completing his master’s degree, he decided to start a PhD in quantum cryptography, to keep secrets truly secret, for ever…

 Merry Christmas from the CNRS team!