Harry Wai Ho Wong

The Applied Cryptography Lab focuses on designing practical cryptographic protocols and systems that balance efficiency, security, and privacy in real-world applications. Current emphasis includes threshold cryptography for decentralized and dynamic settings, privacy-preserving authentication, secure multiparty computation, and countermeasures against cryptographic misuse. The work bridges theoretical foundations with deployable solutions for blockchain, financial systems, anonymous credentials, and beyond.

Research Themes

• Threshold cryptography (e.g., threshold ECDSA/EdDSA/BBS+, best-of-both-worlds designs for dishonest-majority and disruption resilience)
• Privacy-preserving authentication and processing of encrypted/authenticated data
• Secure multiparty computation with improved round/communication efficiency
• Cryptanalysis and secure design of lattice-based schemes and covert channels
• Anonymous tag systems, rate-limiting nullifiers, and double authentication preventing signatures
• Applications to blockchain, central bank digital currencies (CBDCs), and witness encryption

Selected Publications

• Harry W. H. Wong, Jack P. K. Ma, Sherman S. M. Chow. “Secure Multiparty Computation of Threshold Signatures Made More Efficient.” NDSS 2024. (Citations: 10)
• Harry W. H. Wong, Jack P. K. Ma, Hoover H. F. Yin, Sherman S. M. Chow. “Real Threshold ECDSA.” NDSS 2023. (Citations: 24)
• Hoover H. F. Yin, Harry W. H. Wong. “How (Not) to Build Dual-Regev Covert Channel.” IH&MMSec 2025.
• Yingfei Yan, Sherman S. M. Chow, Lucien K. L. Ng, Harry W. H. Wong, Yongjun Zhao, Baocang Wang. “Batch Anonymous MAC Tokens from Lattices.” PQ-Crypto 2025.
• Zhipeng Wang, Orestis Alpos, Alireza Kavousi, Sze Yiu Chau, Duc V. Le, Christian Cachin, Harry W. H. Wong. “DSKE: Digital Signatures with Key Extraction.” CT-RSA 2025. (Citations: 4)
• Harry W. H. Wong, Jack P. K. Ma, Hoover H. F. Yin, Sherman S. M. Chow. “How (Not) to Build Threshold EdDSA.” RAID 2023. (Citations: 5)

Ongoing & Recent Projects

• Best-of-Both-Worlds Threshold Signatures & MPC (2023–present)
  Developing robust, efficient threshold protocols (e.g., ECDSA, BBS+) that support any threshold, resist disruptions, and feature linear communication via novel threshold linearly homomorphic encryption. Adopted in follow-up works by independent groups.
• Dual-Regev Covert Channel Analysis (with Hoover Yin)
  Exploring (in)security of lattice-based covert channels; presented at IH&MMSec 2025.
• Rate-Limiting Nullifiers & Anonymous Tag Systems (ongoing)
  Designing lightweight anonymous rate-limiting mechanisms for blockchains without heavy ZK-SNARKs, with formal security definitions and dynamic membership support.
• Double Authentication Preventing Signatures (ongoing)
  Fine-grained leakage for conflicting authentications in multi-key identity systems, with hierarchical/wildcard extensions for certificate authorities.
• Policy-Based Tracing for CBDCs (future direction)
  Balancing privacy and mandated oversight using selective zero-knowledge revelation of transaction policies.

Join Us

The Applied Cryptography Lab is open to motivated individuals who are enthusiastic about bridging theoretical cryptography with practical, real-world impact. Passion for the field — whether through designing protocols, proving security, implementing prototypes, or exploring new applications — is the most important quality we look for.

We welcome candidates with backgrounds in cryptography, mathematics, computational complexity, or related areas. Proficiency in any of these is valuable:

• Strong mathematical foundations (e.g., algebra, number theory, probability)
• Computer science skills (e.g., algorithms, distributed systems, security theory)
• Programming experience for cryptographic prototypes (e.g., Rust, Go, Python, or similar)

You do not need to excel in all three — being good in one or more, combined with genuine enthusiasm and willingness to learn, is sufficient. We especially encourage applications from those interested in threshold cryptography, privacy-preserving systems, lattice-based schemes, blockchain security, or related topics aligned with the lab's focus.

Opportunities include:

• PhD or MPhil supervision (if applying through NYCU CS programs)
• Visiting scholar/student collaborations
• Undergraduate final-year projects or internships

If this sounds like you, please reach out via email to harrywong0223@hotmail.com with:

• Your CV/resume
• A short note on your research interests and why you'd like to work in the lab (even 1–2 paragraphs is fine)
• Any relevant coursework, projects, code samples, or publications (optional but helpful)