Cryptography is the art and science of keeping information secret. It ensures that messages, data, or files can only be read by those for whom they are intended. Traditional methods encrypt text or data in such a way that it becomes incomprehensible to outsiders and can only be decrypted with a special key. One example is the encryption used in online banking or e-mails.
Quantum cryptography goes one step further: it exploits the special properties of the quantum world, such as single photons and their entanglement. This enables quantum cryptography systems to detect eavesdropping attempts immediately – if someone tries to read the message, the quantum state changes and those involved immediately notice that the connection is no longer secure.
In short: classical cryptography protects our data today, while quantum cryptography takes the security of future communications to a whole new level – virtually unbreakable thanks to the laws of quantum physics.