A revolution is imminent: With the help of quantum mechanical effects, new types of computers could one day quickly solve computing tasks that today’s machines cannot cope with. That is good news. On the one hand. On the other hand, it is bad news. Because commercial computer science as we know it today depends on the existence of computing tasks that computers can cope with. The high computational effort forms a protective wall that secures communication channels. Quantum computers could tear down this protective wall.

Around Lake Zurich, researchers are involved in various teams for the development of post-quantum cryptography. The new encryption methods should protect secrets entrusted to the Internet for decades to come.

For centuries, and even in the late 1970s, it seemed inevitable that the sender and recipient of secret messages would use the same key. This form of protected message exchange is called symmetrical. Since then, asymmetric encryption methods have become generally accepted. They enable the secure exchange of information between two communication partners who are facing each other for the first time and have not had the opportunity to agree on a common key beforehand.

The asymmetric encryption methods use mathematical functions that can only be inverted with great effort. These are one-way or trapdoor functions: In one direction, the passage is easy to pass through, but the way back is blocked. A widely used encryption method is based on the multiplication of two large prime numbers. It does not demand much from a calculating machine, but the opposite way, the prime factorization, is too much for common computers.