A quantum computer uses the effects of quantum mechanics and therefore works differently than conventional computers. While such a device can only perform certain computational operations, it can do so very quickly. In particular, a quantum computer can break all common asymmetric encryption schemes with little effort. Since quantum computers can so far only calculate with very small numbers, they do not yet have any practical significance. However, if this were to change one day, a catastrophe would loom, because many encryptions would then be worthless. Therefore, post-quantum cryptography – which deals with asymmetric methods that are not vulnerable to a quantum computer – is currently an important topic.