Ever since its inception, cryptography has been caught in a vicious circle: Cryptanalysts have always been quick in finding ways to break any supposedly secure encryption scheme, prompting cryptographers to invent even more sophisticated methods to hide information, and so on. But is it actually impossible to develop an unbreakable encryption scheme, or could it be that quantum information technology breaks this vicious circle? Indeed, quantum mechanics offers a variety of unique phenomena which are practically tailor-made for constructing cryptosystems, such as entanglement and the no-cloning theorem. I will explain how these phenomena allow us to build communication schemes whose secrecy relies (almost) only on the laws of physics – leaving basically no room for an attack – and how far we’ve come to date in putting these ideas into practice.