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Luca Nizzardo

Research Scientist / CryptoLab

Education

PhD in Software, Systems, and Computing, 2018

Universidad Politécnica de Madrid

MS in Mathematics, 2013

Università degli Studi di Milano-Bicocca

BS in Mathematics, 2011

Università degli Studi di Milano-Bicocca

Luca is a Cryptography Researcher at Protocol Labs, where he works on crypto-related problems involving Filecoin. Before joining Protocol Labs, Luca did his PhD in Cryptography at Madrid Institute for Advanced Studies in Software under the outstanding supervision of Dario Fiore. He is broadly interested in Blockchain related problems involving cryptography, like Zero Knowledge Proof Systems, Contingent Payments, Consensus Algorithms, and Vector Commitment Schemes.

He has been working on cryptographic techniques for the security of the Cloud since 2014, with a particular focus on homomorphic primitives. Before starting his PhD, he was a business intern at IBM Italy in the Global Business Services division (Fall 2013) and a visiting master student at City College of New York under the supervision of Rosario Gennaro (Spring 2013). During the Spring 2017, he was a visiting PhD student under the supervision of Rosario Gennaro at City College of New York.

Areas of Expertise

Cryptography

Latest work

2020.7.1 / Talks

Vector Commitment Techniques and Applications to Verifiable Decentralized Storage

Vector commitments with subvector openings (SVC) allow one to open a committed vector at a set of positions with an opening of size independent of both the vector's length and the number of opened positions. We continue the study of SVC with two goals in mind: improving their efficiency and making them more suitable to decentralized settings. We address both problems by proposing a new notion for VC that we call incremental aggregation and that allows one to merge openings in a succinct way an unbounded number of times. This property leads to faster generation of openings via preprocessing and a method to generate openings in a distributed way. We then proceed to realize SVC with incremental aggregation. We provide two constructions in groups of unknown order. The first one, similarly to that of Boneh et al. (which supports only one-hop aggregation), has constant-size public parameters, commitments and openings. As an additional feature for this construction we propose efficient arguments of knowledge of subvector openings which immediately yields a keyless proof of storage with compact proofs. For our second construction, we propose an incremental aggregation method for the SVC of Lai-Malavolta; this has linear-size parameters but faster openings. Finally, we address a problem closely related to that of SVC: storing a file efficiently in completely decentralized networks. We introduce and construct verifiable decentralized storage (VDS), a cryptographic primitive that allows to check the integrity of a file stored by a network of nodes in a distributed and decentralized way. Our VDS constructions rely on our new vector commitment techniques.

2020.2.17 / Publications

Vector Commitment Techniques and Applications to Verifiable Decentralized Storage

Vector commitments with subvector openings (SVC) [Lai-Malavolta and Boneh-Bunz-Fisch, CRYPTO'19] allow one to open a committed vector at a set of positions with an opening of size independent of both the vector’s length and the number of opened positions.