1. Teacher ： Hsien-Chu Wu Student ： Hsiao-yun Tseng, Chen-ying Lai Speaker ： Hsiao-yun Tseng Date ： May 10, 2006 Database Temper Detection Techniques Based on Digital Watermarking

2. 2 Outline Introduction Two proposed Methods Method I – for binary watermarks Method II – for grey watermarks Experimental results Conclusions

3. 3 Introduction Data warehouse Market analysis innocent victim payment Stop The purposes of database watermarking: avoid data destroyed and tort malicious damage

4. 4 Produce the certification code Database P Att. A 1 Att. A 2 … Att. A N 1A 11 A 12 …A 1N 2A 21 A 22 …A 2N 3A 31 A 32 …A 3N …………… feature C watermark WM' ⊕ certification code S Key DB SD + Internet SD P Key certification code P Att. A 1 Att. A 2 … Att. A N 1A 11 A 12 …A 1N 2A 21 A 22 …A 2N 3A 31 A 32 …A 3N …………… T T feature C' ⊕ watermark WM'' verification process

5. 5 Method I – for binary watermarks Produce the certification code(1/4) 100101.. WM WM = ECC(WM,S ) WM S=M×N M ： Total tuples of the database N ： Total attributes of the database

6. 6 Method I – for binary watermarks Produce the certification code(2/4) group NO.B_nameDateamountprice 1 Harry potter 11/1 0 100200 2 The Da Vince Code 12/1 5 150400 3 Digital fortess 12/1 6 240410 4 Little women 12/1 7 260380 5 The world is Flat 12/1 6 240200 …………… = 5 × 200 mod 2 = 1000 mod 512 = 488 5 ANS. A i,j = 488 200 A i,j =P i A i,j mod 2 fetch the feature C i,j

7. 7 Method I – for binary watermarks Produce the certification code(3/4) C i,j (A i,j ) C i,j (A i,j ) = ( 不成立 ) ( 成立 ) ANS. C i,j (A i,j ) = 1 NO.B_nameDateamountprice 1Harry potter11/10100200 2 The Da Vince Code 12/15150400 3 Digital fortess 12/16240410 4 Little women 12/17260380 5 The world is Flat 12/16240200 …………… Feature 1

8. 8 Method I – for binary watermarks Produce the certification code(4/4) WM feature C ⊕ certification code AK 000100.. 100001 S Key Database SD + Internet 100101..

9. 9 Method I – for binary watermarks The verification process of database integrity Database SD + Internet SD P Key certification code AK T group fetch the feature 000100.. feature C 100001.. ⊕ 100101 WM  A i,j * =P i * A i,j  mod 2 C i,j (A i,j * )

10. 10 Method I – for binary watermarks Experimental results(1/2) NO.B_nameDateamountprice 1 Harry potter 11/10100200 2 The Da Vince Code 12/15150400 3 Digital fortess 12/16240410 4 Little women 12/17260380 5 The world is Flat 12/16240200 Emulation experiment  Database ： the trade of the network bookstore  table ： Book  tuples ： 10000  attributes ： Book (NO., B_name, Date, amount, price) ‧ the amount of values ： 10000  4 =40000

11. 11 Method I – for binary watermarks Experimental results(2/2) original watermark Exp. 1 ： revise the front 500 B_name Exp. 2 ： revise the last 500 price Result ： find out 390 values to be destroyed Result ： find out 498 values to be destroyed The accuracy rate is 78%. The accuracy rate is 99%.

12. 12 Method II – for grey watermarks Produce the certification code(1/3) watermark WM with size   ×   N ： total tuples of the database original watermark P Att. A 1 Att. A 2 … Att. A N 1A 11 A 12 …A 1N 2A 21 A 22 …A 2N 3A 31 A 32 …A 3N …………… 10000 tuples N = 10000   = 100

13. 13 Method II – for grey watermarks Produce the certification code(2/3) P Att. A 1 Att. A 2 … Att. A N 1A 11 A 12 …A 1N 2A 21 A 22 …A 2N 3A 31 A 32 …A 3N …………… T M i = MD5 (t i ) 10010111001…01011110100… Mi =Mi = 10010111001… 01011110100… ⊕ b i = {0 ~ 63 bits of M i } 11001001101… XiXi X i mod 256 C i f i = {64 ~127 bits of M i }

14. 14 Method II – for grey watermarks Produce the certification code(3/3) feature C ⊕ certification image R SD Database SD + Internet S Key

15. 15 Method II – for grey watermarks The verification process of database integrity Database SD + Internet SD P Key certification image R T fetch the feature C feature C ⊕

16. 16 Method II – for grey watermarks Experimental results(1/4) Emulation experiment  Database Source : ProQuest Digital Dissertations (PQDD)  Build a table in Microsoft SQL 2000 Sever  Attributes ： (Index, Publication number, Title, Author, Degree, School, Pages, Date, Digital formats) original watermark (30 × 30) designed watermark ( 100 × 100 )

17. 17 Method II – for grey watermarks Experimental results(2/4) Exp. 1 ： revise 30 Publication numbers Result ： find out 3 clear hashes and 30 tuples to be destroyed The accuracy rate is 100%. Exp. 2 ： revise the front 2000 Author Result ： find out the clear hashes on the top half fetched watermark and 1,991 tuples to be altered The accuracy rate is 99.55%.

18. 18 Method II – for grey watermarks Experimental results(3/4) Exp. 3 ： revise the last 3000 Pages Result ： find out the clear hashes on the foot half fetched watermark and 2,991 tuples to be altered The accuracy rate is 99.7 %. Exp. 4 ： delete Digital Formats attribute and replace with Degree attribute Result ： find out the clear hashes on the whole fetched watermark and 9,965 tuples to be altered The accuracy rate is 99.65 %.

19. 19 Method II – for grey watermarks Experimental results(4/4) AttackAccuracy rate small alteration100% character alteration99.55% numerical alteration99.7% huge alteration99.65%. Average99.725%

20. 20 The proposed methods prove the integrity of the database and preserve a lossless database In the future, we can hide SD in the database and restore an lossless database. It means to design a reversible database watermarking technique. Conclusions

21. 21 ~ Thank You ~