Morphic Accumulators and Applications: Optimal Range Proofs, Polynomial Commitments, and (Linkable) Ring Signatures
Morphic Accumulators and Applications: Optimal Range Proofs, Polynomial Commitments, and (Linkable) Ring Signatures
Cryptographic accumulators provide a compact way to represent a large set while allowing users to prove that particular elements belong to it.
They are useful in applications ranging from blockchains to authentication and privacy-preserving systems. However, existing accumulators are largely designed for one purpose: proving set membership. In doing so, they typically lose the mathematical relationships among the elements being accumulated.
In this talk, I will introduce morphic accumulators, a new approach that asks a simple question: can an accumulator preserve these relationships while remaining compact and secure? By retaining the algebraic structure of accumulated elements, morphic accumulators make it possible to prove not only that elements belong to a set, but also richer statements about how those elements are related.
I will show how this idea leads to new constructions for three seemingly different cryptographic problems: range proofs, polynomial commitments, and linkable ring signatures. Across these applications, the same underlying technique yields compact proofs and significantly improved efficiency. More broadly, the work illustrates how preserving structure inside a cryptographic primitive can open up capabilities well beyond its original purpose.
Speaker
Jiajun Xin
Jiajun Xin is a postdoctoral researcher at the University of Sydney, working with Prof. Qiang Tang. He received his PhD in Computer Science from the Hong Kong University of Science and Technology (HKUST), advised by Prof. Dimitris Papadopoulos. His research lies at the intersection of applied cryptography and blockchain systems, with a particular focus on zero-knowledge proofs and their applications to secure and privacy-preserving systems. His work bridges cryptographic foundations and real-world applications, including research collaborations with researchers and industry partners from OKX, IOG, and HSBC. His research has been published at leading venues in cryptography, security, and privacy, including CRYPTO, IEEE S&P, USENIX Security, and PoPETs.
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