Anonymous Homomorphic IBE with Application to Anonymous Aggregation

Michael Clear; Ciaran McGoldrick; Hitesh Tewari

Paper 2024/053

Anonymous Homomorphic IBE with Application to Anonymous Aggregation

Michael Clear

, Trinity College Dublin

Ciaran McGoldrick, Trinity College Dublin

Hitesh Tewari, Trinity College Dublin

Abstract

All anonymous identity-based encryption (IBE) schemes that are group homomorphic (to the best of our knowledge) require knowledge of the identity to compute the homomorphic operation. This paper is motivated by this open problem, namely to construct an anonymous group-homomorphic IBE scheme that does not sacrifice anonymity to perform homomorphic operations. Note that even when strong assumptions such as indistinguishability obfuscation (iO) are permitted, no schemes are known. We succeed in solving this open problem by assuming iO and the hardness of the DBDH problem over rings (specifically, $Z_{N^2}$ for RSA modulus $N$). We then use the existence of such a scheme to construct an IBE scheme with re-randomizable anonymous encryption keys, which we prove to be IND-ID-RCCA secure. Finally, we use our results to construct identity-based anonymous aggregation protocols.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Published elsewhere. Minor revision. Cryptography (MDPI)
DOI: 10.3390/cryptography7020022
Keywords: identity-based encryption homomorphic encryption anonymous aggregation
Contact author(s): clearm @ tcd ie
Ciaran McGoldrick @ scss tcd ie
htewari @ tcd ie
History: 2024-01-15: approved; 2024-01-14: received; See all versions
Short URL: https://ia.cr/2024/053
License: CC BY

BibTeX

@misc{cryptoeprint:2024/053,
      author = {Michael Clear and Ciaran McGoldrick and Hitesh Tewari},
      title = {Anonymous Homomorphic {IBE} with Application to Anonymous Aggregation},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/053},
      year = {2024},
      doi = {10.3390/cryptography7020022},
      url = {https://eprint.iacr.org/2024/053}
}