1. A New Data Hiding Scheme with Quality Control for Binary Images Using Block Parity
Mr.M. Venkatesan Mrs.P.MeenakshiDevi
Dr.K.Duraiswamy Dr.K.Thiagarajah
K.S Rangasamy College of Technology,Namakkal Dt,TamiNadu,India
Source:Third International Symposium on Information Assurance and Security, 2007IEEE
Reporter:Liu Rui

2. Outline Introduction Block Data Hiding Method Experimental Results
Conclusion

3. Introduction Hiding data in a binary image
For any bit that is modified in the host image,the bit must be adjacent to another bit that has the same value as the formers new value.

4. Block Data Hiding Method1 1 F1 F2
Partitioned into 3*3 blocks F3 F4
Host image

5. Block Data Hiding Method(cont.)
If Fi is completely black or blank, simply keep Fi intact (not hidden with data) and skip the following steps.
F2=
Computing sum of all elements in the matrix 1 1 1
F1=
F3=
F4=
SUM=5
SUM=8
SUM=4

6. Block Data Hiding Method(cont.)1 1 1
F1=
F3=
F4=
SUM=5
SUM=8
SUM=4
SUM(F1)mod 2=1
SUM(F3)mod 2=0
SUM(F4)mod 2=0
If the parity for the block is odd,then the data embedded is bit 1 and if the parity for
the block is even ,then data embedded is bit 0.
One bit is complemented if the following condition is met:
SUM(Fi)mod 2=0 and embed data is 1 or
SUM(Fi)mod 2=1 and embed data is 0

7. Block Data Hiding Method(cont.)1 1 2 1 2 1 5 2 2
F1=
Neighbour(F1)

8. Block Data Hiding Method(cont.)1 2 1 5
Neighbour(F1)=
F1=
if embed 0 1
F1’=

9. Block Data Hiding Method(cont.)1 1 3
Neighbour(F3)=
F3=
if embed 1 1 1
F3’=
F3’’=

10. Block Data Hiding Method(cont.)1
embed data 010 F1 F2
SUM(F1)=5 SUM(F3)=8 SUM(F4)=4
SUM(F1)mod 2=1 F3 F4
SUM(F3)mod 2=0
SUM(F4)mod 2=0 1
Host image 2 1 5
Neighbour(F1)=

11. Experimental Results
Flower(128×128)
Baboon(131×131)
Lena（131×131）

12. Conclusion
The main idea is to maintain the image quality while increasing the data hiding ratio.
Will not downgrade the image quality based on the amount if can hide.
The hidden data might easily be tampered with,if an illegal user had previous knowledge for retrieving data.