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publications

Cross-Domain Attribute-Based Access Control Encryption

Published in CANS 2021, Vienna, Austria, 2021

In this paper, we propose a constant size Attribute-based Access Control Encryption using a novel CP-ABE. We further improve the trust assumptions by describing the scheme in a more realistic setting called cross-domain ACE.

Tiramisu: Black-Box Simulation Extractable NIZKs in the Updatable CRS Model

Published in CANS 2021, Vienna, Austria, 2021

In this work, we propose a general framework to lift the existing updatable KS NIZKs to stronger notion of Upd-BB-SE.

MLS-ABAC: Efficient multi-level security attribute-based access control scheme

Published in Future Generation Computer Systems (FGCS) journal, 2022

In this work we improve the efficiency of proposed ABE scheme in the previous work using Ascon cryptosystems, and enable multi-level access control using Json Web Tokens (JWT).

Reusable, Instant and Private Payment Guarantees for Cryptocurrencies

Published in ACISP 2023, Brisbane, Australia, 2023

In this paper, we propose a payment guarantee system which improves the through-put and scalability of the existing proof-of-work cryptocurrencies like Bitcoin.

Benchmarking the Setup of Updatable zk-SNARKs

Published in Latincrypt 2023, Sangolquí, Ecuador, 2023

In this paper, we provide a comprehensive benchmarking for the setup of some famous universal and updatable zk-SNARK. We additionally discuss the important notion of updatable knowledge-soundness.

Threshold Structure-Preserving Signatures

Published in Asiacrypt (AC) 2023, Guangzhou, China, 2023

In this paper, we propose the first TSPS with the shortest possible signature while under a restricted class of messages, called index Diffie-Hellman message spaces.

Subset-optimized BLS Multi-signature with Key Aggregation

Published in Financial Crypto (FC) Conference 2024, Willemstad, Curacao, 2024

In this paper, we propose a subset-optimized multi-signature which enables key updateability and efficient public key aggregation.

Threshold Structure-Preserving Signatures: Strong and Adaptive Security under Standard Assumptions

Published in Public Key Cryptography (PKC) Conference 2024, Sydney, Australia, 2024

In this paper, we propose TSPS based on standard assumptions; supporting arbitrary group message vectors. We also prove its security under stronger security notion of T-UF-1 and adaptive adversaries.

Unlinkable Policy-Compliant Signatures for Compliant and Decentralized Anonymous Payments

Published in Privacy-Enhancing Technologies Symposium (PETS) 2024, Bristol, UK, 2024

In this paper, we propose a new primitive called ul-PCS which enables to impose a pre-determined policy in the signature verification process while ensuring the unlinkability of the actions.

zkLogin: Privacy-Preserving Blockchain Authentication with Existing Credentials

Published in ACM CCS, The Salt Lake, USA, 2024

In this paper, we propose zkLogin, that utilizes identity tokens from OpenID Connect platforms (like Google, Microsoft, Meta, etc) for transaction authentication, allowing users to sign with their existing accounts, enhancing user experience by eliminating the need to remember new secrets.

Keyed-Verification Anonymous Credentials with Highly Efficient Partial Disclosure

Published in eprint, 2025

In this paper, we propose two highly efficient KVACs using our novel primitives: SP-MAC-EQ and a homomorphic MAC.

Traceable Verifiable Secret Sharing and Applications

Published in eprint, 2025

In this paper, we introduce TVSS, ensuring both traceability and verifiability, and propose efficient schemes enabling accountable threshold protocols.