Title :
Countering JPEG anti-forensics
Author :
Valenzise, G. ; Nobile, V. ; Tagliasacchi, M. ; Tubaro, S.
Author_Institution :
Dipt. di Elettron. e Inf., Politec. di Milano, Milan, Italy
Abstract :
JPEG coding leaves characteristic footprints that can be leveraged to reveal doctored images, e.g. providing the evidence for local tampering, copy-move forgery, etc. Recently, it has been shown that a knowledgeable attacker might attempt to remove such footprints by adding a suitable anti-forensic dithering signal to the image in the DCT domain. Such noise-like signal restores the distribution of the DCT coefficients of the original picture, at the cost of affecting image quality. In this paper we show that it is possible to detect this kind of attack by measuring the noisiness of images obtained by re-compressing the forged image at different quality factors. When tested on a large set of images, our method was able to correctly detect forged images in 97% of the cases. In addition, the original quality factor could be accurately estimated.
Keywords :
discrete cosine transforms; image coding; DCT domain; JPEG coding; countering JPEG antiforensics; footprints characteristics; image signal; knowledgeable attacker; Discrete cosine transforms; Forensics; Image coding; Noise; Q factor; Quantization; Transform coding; JPEG compression; anti-forensics; digital image forensics;
Conference_Titel :
Image Processing (ICIP), 2011 18th IEEE International Conference on
Conference_Location :
Brussels
Print_ISBN :
978-1-4577-1304-0
Electronic_ISBN :
1522-4880
DOI :
10.1109/ICIP.2011.6115854