Secure authenticated comparisons

  • Authors:
  • Keith B. Frikken;Hao Yuan;Mikhail J. Atallah

  • Affiliations:
  • Computer Science and Software Engineering, Miami University;Department of Computer Science, City University of Hong Kong;Department of Computer Science, Purdue University

  • Venue:
  • ACNS'11 Proceedings of the 9th international conference on Applied cryptography and network security
  • Year:
  • 2011

Quantified Score

Hi-index 0.00

Visualization

Abstract

In the third-party model for the distribution of data, the data owner provides a third party (referred to as the dealer) with data as well as integrity verification information for that data, in the form of digital signatures that the dealer can use to convince a user of the data's integrity (the dealer is not trusted with the owner's signature keys, which is why it receives pre-signed items). The user's interactions are with the dealer, who is in charge of enforcing access control and confidentiality for the data (i.e., no user should learn more than the outcome of their authorized query). This kind of outsourcing is becoming increasingly important because of its advantageous economics - a dealer who acts as a repository for many owners can achieve economies of scale that are not feasible for the individual owners, and the model allows the data owners to focus on what they do best (the creation and/or acquisition of high-quality data). A problem that arises in the context of outsourced databases (particularly for XML data) is the following: There is a total order Π on n items stored with the dealer, and a user query consists of a pair of items whose relative ordering should be revealed along with a proof that the result is correct. The proof is generated using the dealer's local data (i.e., without bothering the data owner). The main difficulty is achieving efficient storage and query-processing while achieving the desiderata (that the user should learn nothing other than the answer to their query, and that a misbehaving dealer should not be able to convince a user of a wrong ordering). This paper gives a solution that is provably secure under a new assumption and can efficiently generate a very short proof. Furthermore, this scheme is generalized to partial orders that can be decomposed into d total orders. In this case, a user either learns the ordering of the queried items, or learns that they are incomparable.