Security Analysis of ePrint Report 2016/500 "Efficient Identity-Based Encryption and Public-Key Signature from Trapdoor Subgroups"

Lucjan Hanzlik; Kamil Kluczniak

Paper 2016/512

Security Analysis of ePrint Report 2016/500 "Efficient Identity-Based Encryption and Public-Key Signature from Trapdoor Subgroups"

Lucjan Hanzlik and Kamil Kluczniak

Abstract

In this short report we analyse the security of three schemes proposed by J. H. Park et al. in "Efficient Identity-Based Encryption and Public-Key Signature from Trapdoor Subgroups". The schemes make use of trapdoor subgroups of $\ZZ_n^*$ and are secure under new assumptions called $q$-Trapdoor Subgroup Diffie-Hellman (TSDH) and $q$-Trapdoor Subgroup Exponent Inversion (TSEI). We show that given several secret keys in case of IBE or several signatures in case of PKS, one can easily extract the trapdoor and break security of the proposed schemes.

Note: This short report is an analysis of the recently published ePrint report 2016/500. Thus, this paper might not be without typos.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint. MINOR revision.
Keywords: attack trapdoor subgroup congruential equations
Contact author(s): lucjan hanzlik @ pwr edu pl
History: 2016-05-29: received
Short URL: https://ia.cr/2016/512
License: CC BY

BibTeX

@misc{cryptoeprint:2016/512,
      author = {Lucjan Hanzlik and Kamil Kluczniak},
      title = {Security Analysis of {ePrint} Report 2016/500 "Efficient Identity-Based Encryption and Public-Key Signature from Trapdoor Subgroups"},
      howpublished = {Cryptology {ePrint} Archive, Paper 2016/512},
      year = {2016},
      url = {https://eprint.iacr.org/2016/512}
}