From Math to Code: Learn Cryptography & Algorithms with a PhD Mentor

Xiao D.

I’m a PhD-trained computer scientist and published researcher who specializes in demystifying modern cryptography. My teaching focus is helping students truly understand cryptography, not just memorize formulas or copy implementations.

My approach connects rigorous mathematics with intuitive, hands-on understanding. Concepts that often feel abstract become clear “aha” moments through carefully designed coding exercises, visualizations, and step-by-step reasoning. Students learn to see the algebraic structure behind cryptographic systems and understand why they work.

This method has been refined over years of teaching and has proven effective for motivated high-school students, software engineers, and graduate-level learners. Students don’t just learn what works, they understand why it works and how to implement it correctly.

I offer a 10-lesson, hands-on cryptography series that guides learners from mathematical foundations to advanced topics in modern cryptography. The full series provides a coherent learning path, while individual lessons may also be taken independently. Each lesson typically runs two hours and is adapted to the learner’s level.

Lesson 1 – Basic number theory, public-key cryptography, RSA
Lesson 2 – Group theory I, Diffie–Hellman key exchange, discrete logarithm problem
Lesson 3 – Group theory II, cyclic groups, subgroups and ElGamal implementation
Lesson 4 – Symmetric cryptography, AES
Lesson 5 – Cryptographic hash functions
Lesson 6 – Elliptic curve cryptography
Lesson 7 – Zero-knowledge proofs
Lesson 8 – Homomorphic encryption
Lesson 9 – Post-quantum and lattice-based cryptography (CKKS)
Lesson 10 – Privacy-preserving ML/AI

I’ve also guided highly motivated high-school students in ISEF-affiliated state science fairs and mentored independent research projects published in very prestigious venues such as the STEM Fellowship Journal.