Intuitive Understanding of Quantum Computation and Post-Quantum Cryptography

Post-quantum cryptography is inevitable. National Institute of Standards and Technology (NIST) starts standardizing quantum-resistant public-key cryptography (aka post-quantum cryptography). The reason is that investment in quantum computing is blooming which poses significant threats to our currently deployed cryptographic algorithms. As a security engineer, to prepare for the apocalypse in advance, I've been watching the development of quantum computers and post-quantum cryptography closely. Never mind, I simply made up an excuse to study these fascinating scientific fields. However, they are extremely hard to understand, at least to an amateur like me. This article shares with you my notes with the hope that you will have an intuitive understanding of the beautiful and mind-blowing quantum algorithms and post-quantum cryptography. Update: Multivariate signature scheme Rainbow is broken by Ward Beullens. Supersingular Isogeny Diffie-Hellman protocol (SIDH) is broken by Wouter Castryck and Thomas Decru