Post-Quantum Cryptography (PQC), highlighting its critical role in safeguarding digital security against the imminent threat of quantum computers. They explain that PQC involves developing new algorithms resistant to quantum attacks, which could otherwise break current encryption methods like RSA and ECC, primarily through Shor's algorithm. The video detail the NIST standardisation process, which has identified key PQC algorithms such as lattice-based ML-KEM and ML-DSA, and hash-based SLH-DSA, with code-based HQC as a backup, noting their varying strengths and weaknesses. They underscore the urgency of PQC migration due to the "Harvest Now, Decrypt Later" threat, where adversaries store encrypted data for future quantum decryption, necessitating a challenging but vital global transition involving hybrid approaches and crypto-agility to future-proof digital infrastructure.