Federated Distributed Key Generation

Fuente: arXiv
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Auteurs principaux: Baranski, Stanislaw, Szymanski, Julian
Format: Preprint
Publié: 2025
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author Baranski, Stanislaw
Szymanski, Julian
author_facet Baranski, Stanislaw
Szymanski, Julian
contents Distributed Key Generation (DKG) underpins threshold cryptography in many systems, including decentralized wallets, validator key ceremonies, cross-chain bridges, threshold signatures, secure multiparty computation, and internet voting. Classical ($t$,$n$)-DKG assumes a fixed group of n parties and a global threshold $t$, requiring full and timely participation. When actual participation deviates, the setup must abort or restart, which is impractical in open or time-critical environments where $n$ is large and availability unpredictable. We introduce Federated Distributed Key Generation (FDKG), inspired by Federated Byzantine Agreement, that makes participation optional and trust heterogeneous. Each participant selects a personal guardian set $G_i$ of size $k$ and a local threshold $t$. Its partial secret can later be reconstructed either by itself or by any t of its guardians. FDKG generalizes PVSS-based DKG and completes both generation and reconstruction in a single broadcast round each, with total communication proportional to $n k$ and at most $O(n^2)$ for reconstruction. Our analysis shows that (i) generation ensures correctness, privacy, and robustness under standard PVSS-based DKG assumptions, and (ii) reconstruction provides liveness and privacy characterized by the guardian-set topology {$G_i$}. Liveness holds if no participant $i$ is corrupted together with at least $k-t+1$ of its guardians. Conversely, privacy is preserved unless the corrupted subset is itself reconstruction-capable.
format Preprint
id arxiv_https___arxiv_org_abs_2502_20835
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Federated Distributed Key Generation
Baranski, Stanislaw
Szymanski, Julian
Cryptography and Security
E.3; C.2
Distributed Key Generation (DKG) underpins threshold cryptography in many systems, including decentralized wallets, validator key ceremonies, cross-chain bridges, threshold signatures, secure multiparty computation, and internet voting. Classical ($t$,$n$)-DKG assumes a fixed group of n parties and a global threshold $t$, requiring full and timely participation. When actual participation deviates, the setup must abort or restart, which is impractical in open or time-critical environments where $n$ is large and availability unpredictable. We introduce Federated Distributed Key Generation (FDKG), inspired by Federated Byzantine Agreement, that makes participation optional and trust heterogeneous. Each participant selects a personal guardian set $G_i$ of size $k$ and a local threshold $t$. Its partial secret can later be reconstructed either by itself or by any t of its guardians. FDKG generalizes PVSS-based DKG and completes both generation and reconstruction in a single broadcast round each, with total communication proportional to $n k$ and at most $O(n^2)$ for reconstruction. Our analysis shows that (i) generation ensures correctness, privacy, and robustness under standard PVSS-based DKG assumptions, and (ii) reconstruction provides liveness and privacy characterized by the guardian-set topology {$G_i$}. Liveness holds if no participant $i$ is corrupted together with at least $k-t+1$ of its guardians. Conversely, privacy is preserved unless the corrupted subset is itself reconstruction-capable.
title Federated Distributed Key Generation
topic Cryptography and Security
E.3; C.2
url https://arxiv.org/abs/2502.20835