Post-quantum Cryptography in 6G
The quantum computing paradigm is fundamentally different from the classical one. There are computational problems we are not able to solve on a contemporary computer, but which we can efficiently solve on a quantum one. One of these problems is the discrete logarithm problem (DLP) which is the basis of modern asymmetric cryptography. Once large-scale quantum computing becomes a reality, these cryptographic primitives need to be replaced with quantum-secure ones. While we are still in the early stages of quantum computing, steps have been taken to prepare for the shift to cryptography that is secure in the post-quantum world. According to the current knowledge, contemporary symmetric cryptography remains secure for the most part even after the advent of quantum computing. Asymmetric primitives based on integer factorization and the DLP need to be replaced. In this chapter, we take a look at the post-quantum secure alternatives for key establishment, public-key encryption and digital signatures. We also discuss their properties and the effect on the performance of the future 6G networks.