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8,503 results · page 210 of 355
Muhammed F. Esgin, Ron Steinfeld, Raymond K. Zhao
No abstract is available for this record.
Nir Bitansky, Sapir Freizeit
No abstract is available for this record.
Zarina Chokparova, Leon Urbas
No abstract is available for this record.
Lalith Medury, Siddhartha Ghosh
No abstract is available for this record.
Xiao-Xu Zhang, Runhua Shi, Wan-Peng Guo, Peng Wang · 5 authors
No abstract is available for this record.
Robi Pedersen, Osmanbey Uzunkol
No abstract is available for this record.
Michele Ciampi, Ivan Visconti
No abstract is available for this record.
Liang Zhang, Feiyang Qiu, Feng Hao, Haibin Kan
Distributed key generation (DKG) is widely used in multi-party computation and decentralized applications. DKG has two phases, namely sharing and reconstruction. Most of the prior DKG protocols need at least 2 rounds for the sharing phase, in case some party raises a dispute. The existing 1-round DKG protocol [Fouqueet al., PKC’01], built based on a publicly verifiable secret sharing (PVSS) scheme, assumes a static adversary model and its reconstruction phase requires$O(n^{2})$communication complexity. Motivated by the observation that a ciphertext-policy attribute-based encryption (CP-ABE) scheme hides secret sharing (SS) in ciphertext, we utilize decentralized CP-ABE to achieve the first adaptively secure 1-round DKG protocol. Firstly, a CP-ABE scheme enables the ciphertexts in DKG to be externally decrypted, making our protocol superior to the PVSS-based DKG protocol in reconstruction. The communication and computation complexities are both lowered to$O(n)$thanks to the constant-sized decryption key and the proposed batch decryption. The use of CP-ABE also makes our DKG protocol storage-friendly, i.e., the parties store no ciphertext after the sharing phase. Secondly, we add non-interactive zero-knowledge (NIZK) proofs to make the CP-ABE ciphertext publicly verifiable by leveraging the sigma protocol and the Fiat-Shamir heuristic. Thirdly, we demonstrate our protocol’s feasibility by presenting a proof-of-concept implementation over Ethereum, which is used as a public channel and a trustworthy computation platform. The implementation is a non-trivial task due to Ethereum’s incompatibility with the bilinear mapping group.
Yuzhu Wang, Mingwu Zhang
No abstract is available for this record.
Yunjia Quan
This paper proposes a novel lattice-based aggregate signature (LAS) scheme that bring post-quantum security to the Bitcoin system without sacrificing its transaction efficiency. Bitcoin currently employs Elliptic Curve Digital Signature Algorithm (ECDSA), which is insecure against the emerging quantum technology, so post-quantum signature schemes like the proposed LAS will become necessary in the near future. However, most of the post-quantum signatures schemes have large signature sizes which decrease Bitcoin’s efficiency while our proposed scheme does not have this negative side effect. Our LAS scheme is based on CRYSTALS-Dilithium and a zero-knowledge Scalable Transparent Arguments of Knowledge (STARK) protocol. CRYSTALS-Dilithium is the most prominent algorithm chosen by the National Institute of Standards and Technology (NIST), yet it still has an adverse limitation: it would cause Bitcoin’s transaction efficiency to fall by 17 times due to its relatively large signature size. On the other hand, the proposed LAS scheme takes full advantage of signature aggregation using the STARK protocol and Dilithium’s easy and fast implementation, thus generating signatures with post-quantum security and small signature sizes which are critical to transaction efficiency. Our proofs convey the correctness, compactness, and post-quantum security of our construction in the quantum random oracle model, and our implementation conveyed that the proposed scheme would only decrease Bitcoin’s transaction efficiency by 3 times, a significant improvement from using Dilithium and other lattice-based aggregate signature schemes. Our proposed scheme has many advantages over the existing schemes and may become very valuable to Bitcoin.
Bertalan Zoltán Péter, Imre Kocsis
Central Bank Digital Currency (CBDC) systems are being developed around the world and production solutions can be expected in the near future. Should a central bank allow handling of CBDC on a ledger that is not under its supervision (via platform bridging), it may wish to specify certain conformance requirements regarding the transactions. We propose a novel audit scheme based on Zero-Knowledge Proofs, which allows the operator of the bridged ledger to prove its compliance to such requirements, without revealing details about the transactions (such as the exact participants, the direction of the transfer, or the transferred value). This scheme aims to resolve the conflict between banks having to audit how CBDC is used on the bridged blockchain and consortia trying to keep sensitive data private.
Daniel Apon, Chloé Cachet, Benjamin Fuller, Peter Hall · 5 authors
No abstract is available for this record.
Jelle Don, Serge Fehr, Christian Majenz, Christian Schaffner
Commit-and-open Sigma-protocols are a popular class of protocols for constructing non-interactive zero-knowledge arguments and digital-signature schemes via the Fiat-Shamir transformation. Instantiated with hash-based commitments, the resulting non-interactive schemes enjoy tight online-extractability in the random oracle model. Online extractability improves the tightness of security proofs for the resulting digital-signature schemes by avoiding lossy rewinding or forking-lemma based extraction. In this work, we prove tight online extractability in the quantum random oracle model (QROM), showing that the construction supports post-quantum security. First, we consider the default case where committing is done by element-wise hashing. In a second part, we extend our result to Merkle-tree based commitments. Our results yield a significant improvement of the provable post-quantum security of the digital-signature scheme Picnic. Our analysis makes use of a recent framework by Chung et al. [arXiv:2010.11658] for analysing quantum algorithms in the QROM using purely classical reasoning. Therefore, our results can to a large extent be understood and verified without prior knowledge of quantum information science.
Kalikinkar Mandal, Guang Gong
No abstract is available for this record.
Jiamin Cui, Kai Hu, Meiqin Wang, Puwen Wei
No abstract is available for this record.
Martin Hrušovský, Gerald Reiner, Alfred Taudes
No abstract is available for this record.
Giuseppe Vitto, Alex Biryukov
No abstract is available for this record.
Alex Chinco
No abstract is available for this record.
Flavio Corradini, Leonardo Mostarda, Emanuele Scala
No abstract is available for this record.
Yashvanth Kondi, Abhi Shelat
No abstract is available for this record.
Rikuo Haga, Kodai Toyoda, Yuto Shinoda, Daiki Miyahara · 7 authors
No abstract is available for this record.
Chaya Ganesh, Hamidreza Khoshakhlagh, Roberto Parisella
No abstract is available for this record.
Helger Lipmaa
No abstract is available for this record.
Valeh Farzaliyev, Jan Willemson, Jaan Kristjan Kaasik
Abstract Mix‐networks were first proposed by Chaum in the late 1970s–early 1980s as a general tool for building anonymous communication systems. Classical mix‐net implementations rely on standard public key primitives (e.g., ElGamal encryption) that will become vulnerable when a sufficiently powerful quantum computer will be built. Thus, there is a need to develop quantum‐resistant mix‐nets. This article focuses on the application case of electronic voting where the number of votes to be mixed may reach hundreds of thousands or even millions. We propose an improved architecture for lattice‐based post‐quantum mix‐nets featuring more efficient zero‐knowledge proofs while maintaining established security assumptions. Our current implementation scales up to 100,000 votes, still leaving a lot of room for future optimisation.