1. Fingerprinting Text in Logical Markup Languages Author : Christian D. Jensen Department of Computer Science Trinity College Dublin ©Springer-Verlag Heidelberg 2001 ISC 2001, LNCS 2200, pp. 433-445, 2001. Presenter: ChaoLi Ou

2. Summary 3 approaches to Fingerprinting text file: Open space – vulnerable to Optical character recognition attack. Syntactic Fingerprinting – easy to recognize. Semantic Fingerprinting-based on synonym substitution Semantic Fingerprinting is the best of three approaches.

3. How does it work ?

4. Comments Appreciated Comment The author explored a new approach to do the fingerprinting in HTML or XML text. The algorithm is simple and clearly outline.

5. Comments Critical Comments: 1.This article doesn’t mention bit rate – How many data can be hidden by the text.

6. Comments My bit-rate estimation: Assumptions 1.One line contains one synonym substitution word 2.The key is: int [3] key Results: Amount of linesBit Rate <30 6120(6x5x4) 10720(10x9x8) 100970,200(100x99x98) Conclusion :Short Text document may not work.

7. Comments (Cont.) 2.[4.2,Sub Attacks, Ln 9] Christian says:“…. However, treason is normally best committed in secret which reduces the risk of collusion among users” One user may have several User Ids to a system (ex, hotmail). No one can prevent a group of people share their synonym substitution text.

8. Comments (Cont) 3.[5.Conclusions,Ln 16] “…simple substitution requires intervention by the user who is fingerprint the document” The user may do a wrong substitution by misunderstanding the document. How does the system protect the author’s “right of integrity”? Question ? Do you agree that we can find the key easily by comparing two or three synonym substitution document ?