CryptoDB
Non-Committing Identity based Encryption: Constructions and Applications
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| Conference: | PKC 2025 |
| Abstract: | A receiver non-committing encryption (RNCE) scheme ~\cite{CFGN96,CHK05} allows one to sample a public key pk and (dummy) ciphertext ct without knowing the message m. Later, when the message is known, one can sample a secret key sk that looks like the secret key corresponding to pk, and decryption of ct produces m. In this work, we study receiver non-committing identity-based encryption (RNC-IBE). We give constructions based on standard assumptions on bilinear groups (prior works~\cite{HMNY21} require indistinguishability obfuscation). Our RNC-IBE constructions have important implications for incompressible identity based encryption. This notion was recently introduced ~\cite{GKRV24}. However, there were no constructions for the strongest security definitions in ~\cite{GKRV24}. Our RNC-IBE scheme also leads to the first incompressible IBE scheme with optimal ciphertext size, which was another open question in \cite{GKRV24}. We also give constructions for relaxed RNC-IBE (where the identity space is polynomial in the security parameter, but the public key is compact) that are based on DDH, LWE. This leads to a relaxed incompressible IBE scheme with strong security from the same assumptions. |
BibTeX
@inproceedings{pkc-2025-35219,
title={Non-Committing Identity based Encryption: Constructions and Applications},
publisher={Springer-Verlag},
author={Rishab Goyal and Fuyuki Kitagawa and Venkata Koppula and Ryo Nishimaki and Mahesh Sreekumar Rajasree and Takashi Yamakawa},
year=2025
}