Military Communications and Information Technology: A Trusted ...

Chapter 4: Information Assurance & Cyber Defence
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keeping from the Filter, which needs to 1) Fetch a latest version of the whole document
from the Storage (cloud); 2) Identify changed elements by their UNSIGNED
HASH CONTENT signature-elements and their correct location in the tree – it is
assumed the User Agent makes use of the tree structure it received from the Filter
(it cannot, for example, remove or relocate parts that contain subelements inaccessible
to it); 3) Replace contents, and their respective WRITE-User and ADMIN-user
signatures; 4) Update security attribute history (recompute the signature as well);
5) Create a new document version (if versioning is in use); and 6) Recompute
the compound element integrity signatures, where elements are merged; recompute
all compound hash values.
VI. Conclusion
In this paper we introduced and canonized a structured content format complying
to multi-level security practices and the cryptographic access control paradigm.
The format was aligned with the XML-standard. We explored the motivation
behind different types of elements and their relatios, as well as the operation with
such a structured document. Our approach was independent of the keying architecture.
Future work includes e.g. many open questions from the re-construction
of a modified document. On a different track, there is also the task to implement
a schema validator and appropriate Filter components for the document.
References
[1] E. Barker, W. Barker, W. Burr, W. Polk, and M. Smid, “Recommendation for Key
Management – Part 1: General (Revised)”, NIST Special Publication 800-57, NIST,
March 2007.
[2] M. Bartel, J. Boyer, B. Fox, B. LaMacchia, and E. Simon, “XML-Signature Syntax
and Processing, W3C Recommendation 12.2.2002”, in http://www.w3.org/TR/2002/
REC-xmldsig-core-20020212/Overview.html, World Wide Web Consortium, 2002
(retrieved 23.4.2012).
[3] D. Bell, L. LaPadula, “Secure Computer Systems: Mathematical Foundations”,
MITRE Technical Report 2547, vol. I, 1.3.1973.
[4] E. Bertino, S. Castano, and E. Ferrari, “On Specifying Security Policies for Web
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[5] E. Bertino, B. Carminati, E. Ferrari, B. Thuraisingham, and A. Gupta, “Selective
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[6] D. Boneh, M. Franklin, “Identity based encryption from the Weil pairing, extended
version”, in SIAM J. of Computing, vol. 32, no. 3, pp. 586-615, 2003.