Paper 2008/466

Combined (identity-based) public key schemes

Maria Isabel Gonzalez Vasco, Florian Hess, and Rainer Steinwandt

Abstract

Consider a scenario in which parties use a public key encryption scheme and a signature scheme with a single public key/private key pair---so the private key sk is used for both signing and decrypting. Such a simultaneous use of a key is in general considered poor cryptographic practice, but from an efficiency point of view looks attractive. We offer security notions to analyze such violations of key separation. For both the identity- and the non-identity-based setting, we show that---although being insecure in general---for schemes of interest the resulting combined (identity-based) public key scheme can offer strong security guarantees.

Metadata
Available format(s)
PDF PS
Category
Public-key cryptography
Publication info
Published elsewhere. Unknown where it was published
Keywords
combined public key schemeidentity-based cryptographykey separation
Contact author(s)
rsteinwa @ fau edu
History
2009-02-04: last of 2 revisions
2008-11-18: received
See all versions
Short URL
https://ia.cr/2008/466
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2008/466,
      author = {Maria Isabel Gonzalez Vasco and Florian Hess and Rainer Steinwandt},
      title = {Combined (identity-based) public key schemes},
      howpublished = {Cryptology ePrint Archive, Paper 2008/466},
      year = {2008},
      note = {\url{https://eprint.iacr.org/2008/466}},
      url = {https://eprint.iacr.org/2008/466}
}
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