Quantum-safe Digital Infrastructures: Technical Challenges and Solutions

As quantum computers become more powerful, existing cryptographic infrastructure faces an existential threat. RSA, elliptic curve cryptography, and Diffie-Hellman key exchange - the algorithms protecting most of today’s digital communications - are all broken by Shor’s algorithm on a sufficiently powerful quantum computer.

This course prepares technical professionals to lead the transition to quantum-safe digital systems. Where the governance course addresses policy and leadership, this course covers the technical side: the cryptography, the trust infrastructure, and the hybrid constructions used during the transition.

Suitable for IT professionals, security engineers, and infrastructure architects preparing organisations for the post-quantum era.

What you’ll learn

• How RSA and elliptic curve cryptography work conceptually and exactly why Shor’s algorithm breaks them - the mathematical structure that quantum period-finding exploits
• Why Grover’s algorithm weakens (but does not break) symmetric cryptography, and what key length increases this implies
• Post-quantum cryptography: the mathematical hard problems believed to be resistant to quantum attacks - lattice problems (Learning With Errors), hash functions, error-correcting codes, and isogenies
• NIST post-quantum standards: ML-KEM (CRYSTALS-Kyber) for key encapsulation, ML-DSA (CRYSTALS-Dilithium) and SLH-DSA (SPHINCS+) for digital signatures
• Why these algorithms are believed to be quantum-resistant and what their security assumptions rest on
• Trust infrastructures for public keys: how current trust hierarchies work and the anatomy of a public key infrastructure (PKI)
• Hybrid security: combining classical and post-quantum algorithms during the transition period, with the advantages and disadvantages of the approach
• Cryptographic combiners: the constructions that join classical and post-quantum schemes into a single hybrid mechanism
• Digital certificates: their structure and purposes, and the hybrid certificate standards emerging for the post-quantum transition

Course structure

The course runs over five weeks at three to four hours per week, self-paced.

Week one introduces cryptography and covers quantum computing and post-quantum cryptography (PQC): which algorithms are threatened and what the post-quantum replacements look like.

Week two covers trust infrastructures for public keys and the anatomy of a PKI: how current trust hierarchies work and where the quantum threat bites.

Week three introduces hybrid security - running classical and post-quantum algorithms together - along with its advantages and disadvantages, and covers cryptographic combiners and specific combiner constructions.

Week four covers the structure and purposes of digital certificates and the hybrid certificate standards emerging for the transition.

Week five offers a first-hand experience with the material and a summary of the key concepts.

Who is this for?

• Security engineers and cryptographers planning or executing post-quantum migrations
• PKI administrators and infrastructure architects assessing quantum-safe readiness
• Software developers who implement cryptographic protocols and need to understand post-quantum replacements
• Technical leaders who need to evaluate vendor claims about quantum-safe products
• Network engineers planning TLS migration for critical infrastructure

Prerequisites

The edX listing states no formal prerequisites - the course opens with an introduction to cryptography and builds from there. That said, familiarity with public-key cryptography, certificate authorities, or PKI management will make the material land faster. No quantum mechanics or quantum computing background is needed - the quantum threat is explained from first principles.

Hands-on practice

Exercises include:

• Working through the anatomy of a PKI and how trust in public keys is established
• Examining hybrid security constructions and weighing their advantages and disadvantages
• Studying specific cryptographic combiner constructions
• Analysing the structure of digital certificates and emerging hybrid certificate standards
• A first-hand experience module in the final week that ties the concepts together

The course does not include implementation programming but engages with the technical concepts at a level of detail that practitioners can use directly.

Why take this course?

Post-quantum cryptography migration is one of the most significant infrastructure challenges of the next decade. NIST finalised its first post-quantum standards in 2024. Major technology vendors (Google, Apple, Cloudflare, Amazon) are shipping post-quantum support in their products now. Regulated industries are beginning to face quantum-safe requirements from government guidance.

Technical professionals who understand post-quantum cryptography deeply - not just at a vocabulary level - will lead these migrations. This course provides that understanding with the credibility of Delft University of Technology. The governance course covers the policy and leadership dimensions; together they form the most complete quantum-safe transition curriculum available online.