Optimizing Segment Based Document Protection
We consider documents with restricted access rights, where some segments of the document are encrypted in order to prevent unauthorized reading. The access rights to such a document are described by an access graph. It is a directed acyclic graph; each node describing a different access rights level. It is assumed that a user having the rights corresponding to a node v has also all rights corresponding to all nodes w such that there is a directed path from v to w in the access graph. Then, to each node v we assign a key Kv and use this key to encrypt the segment of the document corresponding to the access level v.
We consider key management schemes and encoding auxiliary information in the document which ensure that a user who gets a single key corresponding to his access level v can derive all keys Kw for w = v or w being an ancestor of v in the access graph.
In this paper we show how to minimize the total size of auxiliary keying information stored in the document. We provide an algorithm based on node disjoint paths in the access graph and key derivation based on one-way functions. We show that the algorithm chooses the paths in an optimal way.
Keywordsdocument protection access rights key management key hierarchy directed acyclic graph
Unable to display preview. Download preview PDF.
- 1.Qiu, R., Tang, Z., Gao, L., Yu, Y.: A novel XML-based document format with printing quality for web publishing. In: Imaging and Printing in a Web 2.0 World; and Multimedia Content Access: Algorithms and Systems IV. Proc. SPIE, vol. 7540. Society of Photographic Instrumentation Engineers (2010)Google Scholar
- 2.Xu, D., Tang, Z., Yu, Y.: An efficient key management scheme for segment-based document protection. In: 2011 IEEE Consumer Communications and Networking Conference (CCNC), pp. 896–900 (2011)Google Scholar
- 4.Levin, L.A.: The tale of one-way functions (2003), http://arxiv.org/abs/cs.CR/0012023 (retrieved on May 20, 2011)
- 5.Hassen, H.R., Bouabdallah, A., Bettahar, H.: A new and efficient key management scheme for content access control within tree hierarchies. In: AINA Workshops, vol. (1), pp. 551–556. IEEE Computer Society (2007)Google Scholar
- 7.Atallah, M.J., Blanton, M., Fazio, N., Frikken, K.B.: Dynamic and efficient key management for access hierarchies. ACM Trans. Inf. Syst. Secur. 12(3) (2009)Google Scholar