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

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

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

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

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/ The Da Vince Code 12/ Digital fortess 12/ Little women 12/ The world is Flat 12/ …………… Feature 1

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

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 feature C ⊕ WM  A i,j * =P i * A i,j  mod 2 C i,j (A i,j * )

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

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 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 …………… tuples N =   = 100

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 ) … … Mi =Mi = … … ⊕ b i = {0 ~ 63 bits of M i } … XiXi X i mod 256 C i f i = {64 ~127 bits of M i }

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

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 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 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 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 %.

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 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 ~ Thank You ~