Data Authentication for Wireless Sensor Networks with High Detection Efficiency Based on Reversible Watermarking

Algorithm 3

Decoding

Input: stream S'

Output: recovered data stream S

1. while (stream S' is not over) do

2. if (spflag ==0)

3. do steps 3~10 in Algorithm 2;

4. else if (spflag ==1)

5. C ⟵ S₁S_i−1

6. for j ⟵1 to i−1 do

7. pe' ⟵ C_j −

8. w_j ⟵ LSB()

9. if (w_j ≠ W_j)

10. marking G as failed;

11. G ⟵ C//This failed carrier group becomes a new generator group;

12. break

13. else

14. S_j ⟵ (pe' − w_j) /2 + //Restoring the original data;

15. end if

16.  ⟵ ( + C_j) /2

17. end for

18. end if

19. end while