Practical Asynchronous High-threshold Distributed Key Generation and Distributed Polynomial Sampling
Practical Asynchronous High-threshold Distributed Key Generation and Distributed Polynomial Sampling
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发表时间：
2022
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通讯作者：
Sourav Das;Zhuolun Xiang;Lefteris Kokoris-Kogias;Ling Ren
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作者：
Sourav Das;Zhuolun Xiang;Lefteris Kokoris-Kogias;Ling Ren
分布式密钥生成（DKG）是一种在没有可信方的情况下引导门限密码系统的技术。DKG是许多去中心化协议的重要组成部分，如随机信标、阈值签名、拜占庭共识和多方计算。虽然最近已经取得了显着的进展，现有的异步DKG结构是低效的重建阈值时，大于三分之一的总节点。本文提出了一个简单而具体有效的异步DKG（ADKG）协议，该协议在n = 3 t + 1节点间可以容忍最多t个恶意节点，并且支持任意重构阈值<$t ≥ t .我们的协议有一个预期的O（κ n3）的通信成本，其中κ是一个安全参数，并且只假设离散对数的硬度。我们的ADKG协议的核心成分是一个异步协议秘密共享的次数为n ≥ t的随机多项式，它有其他的应用，如异步主动秘密共享和异步多方计算。我们实现了我们的高阈值ADKG协议，并使用多达128个地理上分布的节点的网络进行评估。我们的评估表明，我们的高阈值ADKG协议减少了90%的运行时间，并减少了80%的带宽使用超过国家的最先进的。
Distributed Key Generation (DKG) is a technique to boot-strap 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 and concretely efficient asynchronous DKG (ADKG) protocol among n = 3 t + 1 nodes that can tolerate up to t malicious nodes and support any reconstruction threshold ℓ ≥ t . Our protocol has an expected O ( κ n 3 ) communication cost, where κ is a security parameter, and only assumes the hardness of Discrete Logarithm. The core ingredient of our ADKG protocol is an asynchronous protocol to secret share a random polynomial of degree ℓ ≥ t , which has other applications such as asynchronous proactive secret sharing and asynchronous multiparty computation. We implement our high-threshold ADKG protocol and evaluate it using a network of up to 128 geographically distributed nodes. Our evaluation shows that our high-threshold ADKG protocol reduces the running time by 90% and reduces the bandwidth usage by 80% over state-of-the-art.