Public Key Infrastructure in the Post-Quantum Era

In the last few years the threat of quantum computers has become bigger and bigger. The fast computing of the quantum computers puts everything in danger that relies on classical cryptographic algorithms. The question of when a large-scale quantum computer will be built cannot be exactly answered yet. According to the Cloud Security Alliance at around 2030 the power of quantum computers will increase so that the risk for exposure of traditionally encrypted data will be very high. PKI (Public Key Infrastructure) relies on asymmetric cryptographic algorithms and is widely used in many fields. So it is important that it will be completely safe. The way to provide that is to change traditional cryptographic algorithms to post-quantum cryptography algorithms or hybrid solutions. To this, we review in this paper the basics of classical PKI and quantum cryptography methods and the threat of quantum computing for PKI. We present quantum-safe solutions already in use and recommend new, well-performing solutions for a quantum-resistant PKI by comparison.