(a) Original "Biltmore Estate" image of size 2 256 × 256 pixels, (b) tamper data and their locations, (c) proposed watermark and tampered data-PSNR = 38.30 dB, (d) Zhang-Wang watermark and tampered data-PSNR = 37.97, (e) tampered pixels detected by AgTDM, and (f) tampered pixels detected by ZW approach.
Then we used StirMark and did different attacks to the watermarked images including Blurring, Sharpening, Scaling, adding Gaussian noise, Tampering, data block removal and Cropping.
(a) Original "UNCG" image of size 256 × 256 pixels, (b) tamper data and their locations, (c) proposed watermark and tampered data PSNR = 37.74 dB, (d) Zhang-Wang watermark and tampered data PSNR = 37.87, (e) tampered pixels detected by AgTDM, and (f) tampered pixels detected by ZW approach.
Figure 3(b) shows the tamper data and locations, and this tamper data alter 4211 pixels with (where is the ratio between the number of tampered blocks and the total number of blocks [7]).
Malicious actors may compromise cloud systems and cloud applications in order to gain access to private data as well as remove or tamper the data, so to undermine the trust of users toward the data.
During trial runs last year, cases emerged of local officials tampering with data.
The device doesn't have an on/off switch, a design to prevent a fishing crew from tampering with data collection.
The figures exclude cancer cases, which are currently under separate investigation after the hospital was accused of tampering with data last November.
As result, the extracted watermark after such attacks are still visually detectable and the proposed method is robust to tampering and data blocks removal.
