ScholarlyCommons

Title

A Cryptographic Decentralized Label Model

Author(s)

Jeffrey A Vaughan, University of Pennsylvania
Stephan A. Zdancewic, University of PennsylvaniaFollow

Date of this Version

2007

Document Type

Conference Paper

Recommended Citation

Jeffrey A Vaughan and Stephan A. Zdancewic, "A Cryptographic Decentralized Label Model", . January 2007.

Comments

Jeffrey A. Vaughan and Steve Zdancewic. A Cryptographic Decentralized Label Model. In IEEE 2007 Symposium on Security and Privacy (Oakland), pages 192-206, 2007

DOI: 10.1109/SP.2007.5

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Abstract

Information-flow security policies are an appealing way of specifying confidentiality and integrity policies in information systems. Most previous work on language-based security has assumed that programs run in a closed, managed environment and that they use potentially unsafe constructs, such as declassification, to interface to external communication channels, perhaps after encrypting data to preserve its confidentiality. This situation is unsatisfactory for systems that need to communicate over untrusted channels or use untrusted persistent storage, since the connection between the cryptographic mechanisms used in the untrusted environment and the abstract security labels used in the trusted language environment is ad hoc and unclear.

This paper addresses this problem in three ways: First, it presents a simple, security-typed language with a novel mechanism called packages that provides an abstract means for creating opaque objects and associating them with security labels; well-typed programs in this language enforce noninterference. Second, it shows how to implement these packages using public-key cryptography. This implementation strategy uses a variant of Myers and Liskov's decentralized label model, which supports a rich label structure in which mutually distrusting data owners can specify independent confidentiality and integrity requirements. Third, it demonstrates that this implementation of packages is sound with respect to Dolev-Yao style attackers-such an attacker cannot determine the contents of a package without possessing the appropriate keys, as determined by the security label on the package.