Paper 2012/379

All-But-Many Encryption: A New Framework for Fully-Equipped UC Commitments

Eiichiro Fujisaki

Abstract

We present a general framework for constructing non-interactive universally composable (UC) commitment schemes that are secure against adaptive adversaries in the non-erasure model under a re-usable common reference string. Previously, such ``fully-equipped'' UC commitment schemes have been known only in [CF01,CLOS02], with strict expansion factor O(k); meaning that to commit L bits, communication strictly requires O(Lk)$ bits, where k denotes the security parameter. Efficient construction of a fully-equipped UC commitment scheme is a long-standing open problem. We introduce new abstraction, called all-but-many encryption (ABME), and prove that it captures fully-equipped UC commitment schemes. We propose the first fully-equipped UC commitment scheme with optimal expansion factor O(1) from our ABME scheme related to the DCR assumption. We also provide an all-but-many lossy trapdoor function (ABM-LTF)[Hof12] from our DCR-based ABME scheme, with a better lossy rate than [Hof12].

Note: This is the full version.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
A major revision of an IACR publication in ASIACRYPT 2014
Keywords
universal composable commitmentsall-but-many encryptionand all-but-many lossy trapdoor functions
Contact author(s)
eiichiro fujisaki @ gmail com
History
2016-06-16: last of 6 revisions
2012-07-05: received
See all versions
Short URL
https://ia.cr/2012/379
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2012/379,
      author = {Eiichiro Fujisaki},
      title = {All-But-Many Encryption: A New Framework for Fully-Equipped UC Commitments},
      howpublished = {Cryptology ePrint Archive, Paper 2012/379},
      year = {2012},
      note = {\url{https://eprint.iacr.org/2012/379}},
      url = {https://eprint.iacr.org/2012/379}
}
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