Paper 2023/1699 Original: eprint.iacr.org/2023/1699 ↗
Oblivious Homomorphic Encryption
Abstract
In this paper, we introduce Oblivious Homomorphic Encryption (OHE) which provably separates the computation spaces of multiple clients of a fully homomorphic encryption (FHE) service while keeping the evaluator blind about whom a result belongs. We justify the importance of this strict isolation property of OHE by showing an attack on a recently proposed key-private cryptocurrency scheme. Our two OHE constructions are based on a puncturing function where the evaluator can effectively mask ciphertexts from rogue and potentially colluding clients. In the first construction OHE1, we show that this can be im- plemented via an FHE scheme (with key privacy and weak wrong-key decryption properties) plus an anonymous commitment scheme. The second construction OHE2, for flexibility of primitive choice, achieves this via a combination of a standard FHE scheme, an encryption scheme with key privacy and weak wrong-key decryption, and an anonymous commitment scheme. OHE can be used to provide provable anonymity to cloud applications, single server implementations of anonymous messaging as well as account-based cryptocurrencies.
Metadata
- Available format(s)
PDF- Category
- Cryptographic protocols
- Publication info
- Preprint.
- History
- 2023-11-14: last updated
- 2023-11-02: published
- Short URL
- https://ia.cr/2023/1699
- License
- https://creativecommons.org/licenses/by-nc-sa/4.0/
BibTeX
@misc{cryptoeprint:2023/1699,
author = {Osman Biçer and Christian Tschudin},
title = {Oblivious Homomorphic Encryption},
howpublished = {Cryptology {ePrint} Archive, Paper 2023/1699},
year = {2023},
url = {https://eprint.iacr.org/2023/1699}
}