Databases Reference
In-Depth Information
Finally, Zhou, Pang, and Tan [25] proposed creating queries to identify
the data elements in XML data that can be used for embedding watermarks.
The identifying queries are resilient against data reorganization and redun-
dancy removal through query rewriting. If an identified element is a leaf node,
watermark insertion is performed by modifying its value; otherwise, it is per-
formed by adding to or deleting its child nodes. The usability of XML data is
measured by query templates. The results of certain basic queries on the data
remain useful after watermarking or attacks.
8OpenIssues
The current research on database watermarking has been primarily focused
on how to embed and detect a watermark so that the embedded watermark
is robust or fragile against various database attacks. However, the study on
the impact of watermarking to database usability is relatively limited and
preliminary, especially in application contexts. This type of study is important
since one of the greatest concerns in database applications is the usability of
the data, which should not be affected by the watermarking process.
One future research direction is to model common database queries and
minimize the watermarking impact on those queries. It is possible that differ-
ent watermarking schemes should be designed to accommodate different types
of queries. Another future research direction is to model various database at-
tacks that exist in real-world settings. Special attention should be directed to-
ward the impact of those attacks on watermark design and database usability.
Finally, it is meaningful to collect typical real-world data sets, to standardize
database usability measurements and database attack models, and to bench-
mark/ evaluate/ compare various watermarking schemes for typical database
applications.
References
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3. D. Boneh and J. Shaw. Collusion secure fingerprinting for digital data.
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4. I.J. Cox, M.L. Miller, and J.A. Bloom.
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Practice
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The Washington Times
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March 1, 2004. http://www.washingtontimes.com.
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