Deep dive into a post-quantum key encapsulation algorithm

The text discusses key exchange algorithms, which are essential for secure communication over the internet. These algorithms enable two parties to exchange information without ever having to meet in advance. Key exchange algorithms are based on hard mathematical problems such as integer factorization and the discrete logarithm problem. However, these problems can be efficiently solved by a quantum computer, breaking the secrecy of the communication. The text introduces Key Encapsulation Mechanisms (KEMs) and explains how they work. It also discusses the use of KEMs in modern internet connections and presents an example of a post-quantum KEM called FrodoKEM. The security of FrodoKEM is based on the hardness of the Learning With Errors (LWE) problem over lattices. The text further explains how to build encryption from this mathematical base using Public Key Encryption (PKE) and Key Encapsulation Mechanisms (KEMs). It also mentions other KEMs beyond Frodo, such as Kyber, NTRU, Saber, and Classic McEliece.