Paper 2005/378 Original: eprint.iacr.org/2005/378 ↗
A New Protocol for Conditional Disclosure of Secrets And Its Applications
Abstract
Many protocols that are based on homomorphic encryption are private only if a client submits inputs from a limited range $S$. Conditional disclosure of secrets (CDS) helps to overcome this restriction. In a CDS protocol for a set $S$, the client obtains server's secret if and only if the client's inputs belong to $S$ and thus the server can guard itself against malformed queries. We extend the existing CDS protocols to work over additively homomorphic cryptosystems for every set from $NP/poly$. The new construction is modular and easy to apply. As an example, we derive a new oblivious transfer protocol with log-squared communication and a millionaire's protocol with logarithmic communication. We also implement private, universally verifiable and robust multi-candidate electronic voting so that all voters only transmit an encryption of their vote. The only hardness assumption in all these protocols is that the underlying public-key cryptosystem is IND-CPA secure and the plaintext order does not have small factors.
Metadata
- Available format(s)
PDF- Category
- Cryptographic protocols
- Publication info
- Preprint.
- History
- 2007-03-20: last updated
- 2005-10-23: published
- Short URL
- https://ia.cr/2005/378
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2005/378,
author = {Sven Laur and Helger Lipmaa},
title = {A New Protocol for Conditional Disclosure of Secrets And Its Applications},
howpublished = {Cryptology {ePrint} Archive, Paper 2005/378},
year = {2005},
url = {https://eprint.iacr.org/2005/378}
}