Reactive Correctness, sINDCPA-D-Security and Deterministic Evaluation for TFHE

Nigel Smart; Michael Walter

Paper 2025/2005

Reactive Correctness, sINDCPA-D-Security and Deterministic Evaluation for TFHE

Nigel Smart

, KU Leuven, Zama

Michael Walter

Abstract

We examine the relationship between correctness definitions for Fully Homomorphic Encryption (FHE) and the associated security definitions. We show that reactive notions of correctness imply INDCPA-D and sINDCPA-D security. But that to obtain both INDCPA-D and sINDCPA-D security we need to use a randomized version of the evaluation procedure. Such randomized evaluation procedures cause problems in real life deployments of FHE solutions, so we then go on to show how one can de-randomize the evaluation procedure and still obtain sINDCPA-D security in the random oracle model for the specific FHE scheme of TFHE.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint.
Keywords: Homomorphic Encryption
Contact author(s): nigel @ zama ai
michael walter @ zama ai
History: 2025-10-30: approved; 2025-10-27: received; See all versions
Short URL: https://ia.cr/2025/2005
License: CC BY

BibTeX

@misc{cryptoeprint:2025/2005,
      author = {Nigel Smart and Michael Walter},
      title = {Reactive Correctness, {sINDCPA}-D-Security and Deterministic Evaluation for {TFHE}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/2005},
      year = {2025},
      url = {https://eprint.iacr.org/2025/2005}
}