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arXiv · 2110.04293

Function-private Conditional Disclosure of Secrets and Multi-evaluation Threshold Distributed Point Functions

Nolan Miranda·Foo Yee Yeo·Vipin Singh Sehrawat
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Abstract

Conditional disclosure of secrets (CDS) allows multiple parties to reveal a secret to a third party if and only if some pre-decided condition is satisfied. In this work, we bolster the privacy guarantees of CDS by introducing function-private CDS wherein the pre-decided condition is never revealed to the third party. We also derive a function secret sharing scheme from our function-private CDS solution. The second problem that we consider concerns threshold distributed point functions, which allow one to split a point function such that at least a threshold number of shares are required to evaluate it at any given input. We consider a setting wherein a point function is split among a set of parties such that multiple evaluations do not leak non-negligible information about it. Finally, we present a provably optimal procedure to perform threshold function secret sharing of any polynomial in a finite field.

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Nolan Miranda, Foo Yee Yeo, Vipin Singh Sehrawat. 2021-10-08. Function-private Conditional Disclosure of Secrets and Multi-evaluation Threshold Distributed Point Functions. https://arxiv.org/abs/2110.04293

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