9 results sorted by ID
Asynchronous Verifiable Secret Sharing with Elastic Thresholds and Distributed Key Generation
Junming Li, Zhi Lu, Renfei Shen, Yuanqing Feng, Songfeng Lu
Public-key cryptography
Distributed Key Generation (DKG) is a technique that enables the generation of threshold cryptography keys among a set of mutually untrusting nodes. DKG generates keys for a range of decentralized applications such as threshold signatures, multiparty computation, and Byzantine consensus. Over the past five years, research on DKG has focused on optimizing network communication protocols to improve overall system efficiency by reducing communication complexity. However, SOTA asynchronous...
Haven++: Batched and Packed Dual-Threshold Asynchronous Complete Secret Sharing with Applications
Nicolas Alhaddad, Mayank Varia, Ziling Yang
Cryptographic protocols
Asynchronous complete secret sharing (ACSS) is a foundational primitive in the design of distributed algorithms and cryptosystems that require secrecy. Dual-threshold ACSS permits a dealer to distribute a secret to a collection of $n$ servers so that everyone holds shares of a polynomial containing the dealer's secret.
This work contributes a new ACSS protocol, called Haven++, that uses packing and batching to make asymptotic and concrete advances in the design and application of ACSS for...
FIN: Practical Signature-Free Asynchronous Common Subset in Constant Time
Sisi Duan, Xin Wang, Haibin Zhang
Cryptographic protocols
Asynchronous common subset (ACS) is a powerful paradigm enabling applications such as Byzantine fault-tolerance (BFT) and multi-party computation (MPC). The most efficient ACS framework in the information-theoretic setting is due to Ben-Or, Kelmer, and Rabin (BKR, 1994). The BKR ACS protocol has been both theoretically and practically impactful. However, the BKR protocol has an $O(\log n)$ running time (where $n$ is the number of replicas) due to the usage of $n$ parallel asynchronous...
Bingo: Adaptivity and Asynchrony in Verifiable Secret Sharing and Distributed Key Generation
Ittai Abraham, Philipp Jovanovic, Mary Maller, Sarah Meiklejohn, Gilad Stern
Cryptographic protocols
We present Bingo, an adaptively secure and optimally resilient packed asynchronous verifiable secret sharing (PAVSS) protocol that allows a dealer to share $f+1$ secrets with a total communication complexity of $O(\lambda n^2)$ words, where $\lambda$ is the security parameter and $n$ is the number of parties. Using Bingo, we obtain an adaptively secure validated asynchronous Byzantine agreement (VABA) protocol that uses $O(\lambda n^3)$ expected words and constant expected time, which we in...
Practical Asynchronous Distributed Key Generation: Improved Efficiency, Weaker Assumption, and Standard Model
Haibin Zhang, Sisi Duan, Chao Liu, Boxin Zhao, Xuanji Meng, Shengli Liu, Yong Yu, Fangguo Zhang, Liehuang Zhu
Cryptographic protocols
Distributed key generation (DKG) allows bootstrapping threshold cryptosystems without relying on a trusted party, nowadays enabling fully decentralized applications in blockchains and multiparty computation (MPC). While we have recently seen new advancements for asynchronous DKG (ADKG) protocols, their performance remains the bottleneck for many applications, with only one protocol being implemented (DYX+ ADKG, IEEE S&P 2022). DYX+ ADKG relies on the Decisional Composite Residuosity...
Practical Asynchronous High-threshold Distributed Key Generation and Distributed Polynomial Sampling
Sourav Das, Zhuolun Xiang, Lefteris Kokoris-Kogias, Ling Ren
Cryptographic protocols
Distributed Key Generation (DKG) is a technique to bootstrap threshold cryptosystems without a trusted party. DKG is an essential building block to many decentralized protocols such as randomness beacons, threshold signatures, Byzantine consensus, and multiparty computation. While significant progress has been made recently, existing asynchronous DKG constructions are inefficient when the reconstruction threshold is larger than one-third of the total nodes. In this paper, we present a simple...
Practical Asynchronous Distributed Key Generation
Sourav Das, Thomas Yurek, Zhuolun Xiang, Andrew Miller, Lefteris Kokoris-Kogias, Ling Ren
Cryptographic protocols
Distributed Key Generation (DKG) is a technique to bootstrap threshold cryptosystems without a trusted third party and is a building block to decentralized protocols such as randomness beacons, threshold signatures, and general multiparty computation. Until recently, DKG protocols have assumed the synchronous model and thus are vulnerable when their underlying network assumptions do not hold. The recent advancements in asynchronous DKG protocols are insufficient as they either have poor...
Asynchronous Data Dissemination and its Applications
Sourav Das, Zhuolun Xiang, Ling Ren
Cryptographic protocols
In this paper, we introduce the problem of Asynchronous Data Dissemination (ADD). Intuitively, an ADD protocol disseminates a message to all honest nodes in an asynchronous network, given that at least $t+1$ honest nodes initially hold the message where $t$ is the maximum number of malicious nodes.
We design a simple and efficient ADD protocol for $n$ parties that is information-theoretically secure, tolerates up to one-third malicious nodes, and has a communication cost of $O(n|M|+n^2)$ for...
Asynchronous Distributed Key Generation for Computationally-Secure Randomness, Consensus, and Threshold Signatures.
Eleftherios Kokoris-Kogias, Dahlia Malkhi, Alexander Spiegelman
Public-key cryptography
In this paper, we present the first fully asynchronous distributed key generation (ADKG) algorithm as well as the first distributed key generation algorithm that can create keys with a dual $(f,2f+1)-$threshold that are necessary for scalable consensus (which so far needs a trusted dealer assumption).
In order to create a DKG with a dual $(f,2f+1)-$ threshold we first answer in the affirmative the open question posed by Cachin et al. how to create an AVSS protocol with recovery thresholds $...
Distributed Key Generation (DKG) is a technique that enables the generation of threshold cryptography keys among a set of mutually untrusting nodes. DKG generates keys for a range of decentralized applications such as threshold signatures, multiparty computation, and Byzantine consensus. Over the past five years, research on DKG has focused on optimizing network communication protocols to improve overall system efficiency by reducing communication complexity. However, SOTA asynchronous...
Asynchronous complete secret sharing (ACSS) is a foundational primitive in the design of distributed algorithms and cryptosystems that require secrecy. Dual-threshold ACSS permits a dealer to distribute a secret to a collection of $n$ servers so that everyone holds shares of a polynomial containing the dealer's secret. This work contributes a new ACSS protocol, called Haven++, that uses packing and batching to make asymptotic and concrete advances in the design and application of ACSS for...
Asynchronous common subset (ACS) is a powerful paradigm enabling applications such as Byzantine fault-tolerance (BFT) and multi-party computation (MPC). The most efficient ACS framework in the information-theoretic setting is due to Ben-Or, Kelmer, and Rabin (BKR, 1994). The BKR ACS protocol has been both theoretically and practically impactful. However, the BKR protocol has an $O(\log n)$ running time (where $n$ is the number of replicas) due to the usage of $n$ parallel asynchronous...
We present Bingo, an adaptively secure and optimally resilient packed asynchronous verifiable secret sharing (PAVSS) protocol that allows a dealer to share $f+1$ secrets with a total communication complexity of $O(\lambda n^2)$ words, where $\lambda$ is the security parameter and $n$ is the number of parties. Using Bingo, we obtain an adaptively secure validated asynchronous Byzantine agreement (VABA) protocol that uses $O(\lambda n^3)$ expected words and constant expected time, which we in...
Distributed key generation (DKG) allows bootstrapping threshold cryptosystems without relying on a trusted party, nowadays enabling fully decentralized applications in blockchains and multiparty computation (MPC). While we have recently seen new advancements for asynchronous DKG (ADKG) protocols, their performance remains the bottleneck for many applications, with only one protocol being implemented (DYX+ ADKG, IEEE S&P 2022). DYX+ ADKG relies on the Decisional Composite Residuosity...
Distributed Key Generation (DKG) is a technique to bootstrap threshold cryptosystems without a trusted party. DKG is an essential building block to many decentralized protocols such as randomness beacons, threshold signatures, Byzantine consensus, and multiparty computation. While significant progress has been made recently, existing asynchronous DKG constructions are inefficient when the reconstruction threshold is larger than one-third of the total nodes. In this paper, we present a simple...
Distributed Key Generation (DKG) is a technique to bootstrap threshold cryptosystems without a trusted third party and is a building block to decentralized protocols such as randomness beacons, threshold signatures, and general multiparty computation. Until recently, DKG protocols have assumed the synchronous model and thus are vulnerable when their underlying network assumptions do not hold. The recent advancements in asynchronous DKG protocols are insufficient as they either have poor...
In this paper, we introduce the problem of Asynchronous Data Dissemination (ADD). Intuitively, an ADD protocol disseminates a message to all honest nodes in an asynchronous network, given that at least $t+1$ honest nodes initially hold the message where $t$ is the maximum number of malicious nodes. We design a simple and efficient ADD protocol for $n$ parties that is information-theoretically secure, tolerates up to one-third malicious nodes, and has a communication cost of $O(n|M|+n^2)$ for...
In this paper, we present the first fully asynchronous distributed key generation (ADKG) algorithm as well as the first distributed key generation algorithm that can create keys with a dual $(f,2f+1)-$threshold that are necessary for scalable consensus (which so far needs a trusted dealer assumption). In order to create a DKG with a dual $(f,2f+1)-$ threshold we first answer in the affirmative the open question posed by Cachin et al. how to create an AVSS protocol with recovery thresholds $...