Recent claims of quantum supremacy have sparked renewed interest in cryptography in the post-
quantum era. The development of post-quantum cryptographic systems for classical computers capable of preventing attacks launched by quantum computers is referred to as post-quantum
cryptography. After mathematician Peter Shor successfully demonstrated that a theoretical quantum computer could easily break the algorithm used for public-key encryption (PKE) in the 1990s, cryptographers all over the world began to speculate on what a post-quantum cryptography system might look like.

​

     In terms of public-key PQC, there are five well-known and commonly cited classes of cryptographic primitives that are believed to remain secure in the presence of a quantum computer: code-based cryptography, lattice-based cryptography, hash-based cryptography, multivariate cryptography, and isogeny-based cryptography. However, large-scale quantum computers capable of breaking cryptography are unlikely to emerge in the next decade. Nonetheless, systems that require very long-term protection must begin preparing to replace today's classical algorithms.