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zeekay
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Restructured from flat .tex/.pdf files into per-paper subdirectories. Added Antje Worring as co-author on all papers. Synced PDFs to pdfs/ for download site.
52 lines
2.1 KiB
TeX
52 lines
2.1 KiB
TeX
\section{Protocol Overview}
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\label{sec:overview}
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\subsection{Phases}
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State sync proceeds in four phases:
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\begin{enumerate}
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\item \textbf{Checkpoint selection}: The syncing node identifies a recent finalized block whose state root will be the sync target.
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\item \textbf{Chunk discovery}: The node requests the trie's top-level structure to plan parallel downloads.
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\item \textbf{Chunk download}: State chunks are downloaded from multiple peers in parallel, each verified independently.
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\item \textbf{Completion}: The node verifies that all chunks assemble into the target state root and begins processing new blocks.
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\end{enumerate}
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\begin{algorithm}[H]
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\caption{State Sync Main Loop}
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\label{alg:main}
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\begin{algorithmic}[1]
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\Require Target state root $R$ from finalized block $B$
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\State $\mathcal{C} \gets \mathsf{PlanChunks}(R)$ \Comment{Identify chunks}
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\State $\mathsf{pending} \gets \mathcal{C}$; $\mathsf{completed} \gets \emptyset$
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\While{$\mathsf{pending} \neq \emptyset$}
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\For{each available peer $p$ \textbf{in parallel}}
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\State $c \gets \mathsf{pending}.\mathsf{pop}()$
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\State $(data, \pi) \gets \mathsf{RequestChunk}(p, c)$
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\If{$\mathsf{VerifyChunk}(data, \pi, R)$}
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\State $\mathsf{completed} \gets \mathsf{completed} \cup \{c\}$
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\State Write $data$ to local database
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\Else
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\State $\mathsf{pending}.\mathsf{push}(c)$ \Comment{Retry from different peer}
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\State Ban peer $p$
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\EndIf
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\EndFor
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\EndWhile
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\State Verify $\mathsf{ReconstructRoot}(\mathsf{completed}) = R$
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\end{algorithmic}
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\end{algorithm}
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\subsection{Checkpoint Selection}
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\begin{definition}[Sync Checkpoint]
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A sync checkpoint is a block $B$ satisfying:
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\begin{enumerate}
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\item $B$ is finalized (accepted by consensus with $\geq 2/3$ stake).
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\item $B$'s height is $\leq H_{\text{current}} - \Delta_{\text{safe}}$ where $\Delta_{\text{safe}} = 1000$ blocks.
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\item $B$ is an epoch boundary block (height divisible by epoch length).
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\end{enumerate}
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\end{definition}
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The safety margin $\Delta_{\text{safe}}$ ensures the state root is deeply finalized and unlikely to be reorganized.
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