Paper 2015/153

Functional Encryption from (Small) Hardware Tokens

Kai-Min Chung, Jonathan Katz, and Hong-Sheng Zhou


Functional encryption (FE) enables fine-grained access control of encrypted data while promising simplified key management. In the past few years substantial progress has been made on functional encryption and a weaker variant called predicate encryption. Unfortunately, fundamental impossibility results have been demonstrated for constructing FE schemes for general functions satisfying a simulation-based definition of security. We show how to use \emph{hardware tokens} to overcome these impossibility results. In our envisioned scenario, an authority gives a hardware token and some cryptographic information to each authorized user; the user combines these to decrypt received ciphertexts. Our schemes rely on \emph{stateless} tokens that are \emph{identical} for all users. (Requiring a different token for each user trivializes the problem, and would be a barrier to practical deployment.) The tokens can implement relatively ``lightweight'' computation relative to the functions supported by the scheme. Our token-based approach can be extended to support hierarchal functional encryption, function privacy, and more.

Available format(s)
Publication info
Published by the IACR in ASIACRYPT 2013
Contact author(s)
hszhou @ vcu edu
2015-05-04: revised
2015-02-27: received
See all versions
Short URL
Creative Commons Attribution


      author = {Kai-Min Chung and Jonathan Katz and Hong-Sheng Zhou},
      title = {Functional Encryption from (Small) Hardware Tokens},
      howpublished = {Cryptology ePrint Archive, Paper 2015/153},
      year = {2015},
      note = {\url{}},
      url = {}
Note: In order to protect the privacy of readers, does not use cookies or embedded third party content.