DrSri AravindaKrishnan Thyagarajan

Title: Cryptography for Modern Applications

Project summary (student-facing):
How do you let a bunch of mutually suspicious users compute and move money together without a central authority—and without anyone getting cheated or spied on? In this project we design and analyse new cryptographic protocols for modern distributed systems such as blockchains, cryptocurrencies and cloud platforms. The aim is to build schemes that are secure, private, fair, and efficient, with proofs on paper and prototypes in code.

Research area keywords:
Cryptography · Blockchain · Game Theory · Distributed Systems · Post-Quantum

You’ll work on problems of the form:

• Multiple parties each hold private data (or assets) and want to compute / transact without trusting a central party.

• We want security and privacy: no one learns more than they should.

• We want fairness and accountability: nobody can abort, cheat, or walk away with an unfair advantage—and rational players have no incentive to misbehave.

Typical tasks include:

• Designing formal security and fairness definitions for new distributed settings (e.g., new blockchain protocols, agentic payments, privacy-preserving cloud services).

• Building cryptographic protocols and algorithms that realise these definitions.

• Proving security using reduction-based proofs (in the spirit of complexity-theoretic reductions).

• Implementing proof-of-concept prototypes and, where relevant, benchmarking them on realistic workloads.

The overarching theme is to use well-understood mathematical structures to build practical, deployable mechanismsthat can feed into real systems.

• Duration: 3.5 years

• Stipend: RTP rate (currently $40,109 in 2024)

• Fees: Tuition fees covered for international candidates

You’ll be supervised by Dr Sri AravindaKrishnan (“Aravind”) Thyagarajan in the School of Computer Science at the University of Sydney, working in a small, research-active group at the intersection of cryptography, blockchains and game theory.

Successful candidates should:

• Hold a Bachelor’s degree with 1st class Honours (or equivalent), or a Master’s degree.

• Have a solid understanding of probability theory and algorithms.

• Have background in complexity theory and mathematics, especially number theory and abstract algebra (or be keen to learn).

• Have programming experience (any modern language); systems / crypto implementation experience is a bonus but not required.

Email aravind.thyagarajan@sydney.edu.au with:

• Your CV

• Your academic transcripts

Feel free to include a short note about your interests (e.g., “I’d like to work on post-quantum protocols for blockchains” or “I like theory but also want to code”).