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zeekay abf99d05fc papers: reorganize into per-paper dirs, add Antje Worring as co-author
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Added Antje Worring as co-author on all papers.
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2026-04-18 21:50:07 -07:00

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\section{Introduction}
\label{sec:introduction}
Fully Homomorphic Encryption (FHE) enables computation on encrypted data without
decrypting it, a capability with profound implications for blockchain privacy.
Smart contracts operating on encrypted inputs can implement confidential token transfers,
private auctions, sealed-bid voting, and encrypted machine learning inference---all
without revealing the underlying data to validators or observers.
TFHE (Torus FHE)~\cite{chillotti2020tfhe} is the leading boolean-circuit FHE scheme,
encrypting individual bits and evaluating gates through a bootstrapping procedure that
refreshes the noise after each gate. Unlike CKKS (which operates on approximate
arithmetic) or BGV/BFV (which operate on integer arithmetic), TFHE's bit-level
granularity is ideally suited for arbitrary computation: any function expressible as a
boolean circuit can be evaluated gate-by-gate.
This paper extends TFHE with threshold decryption for blockchain applications: the secret
key is distributed among $n$ validators via Shamir sharing, and any $t$ validators can
collaboratively decrypt the result without reconstructing the full key. This is critical
for decentralized FHE, where no single party should possess the decryption capability.
\paragraph{Contributions.}
\begin{enumerate}[nosep]
\item A complete description of the TFHE boolean gate evaluation pipeline, including
the blind rotation and CMPCOMBINE optimization (\S\ref{sec:tfhe}).
\item Threshold decryption protocol with security proof under LWE (\S\ref{sec:threshold}).
\item Concrete parameter selection and security analysis (\S\ref{sec:params}).
\item Integration with the Lux FHE VM for on-chain encrypted computation (\S\ref{sec:fhevm}).
\item Benchmarks for all boolean gates and multi-bit operations (\S\ref{sec:evaluation}).
\end{enumerate}
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