On antiforensic concealability with rate-distortion tradeoff

Area of Science:

• Digital Forensics
• Image Processing
• Information Security

Background:

• Signal compression history is crucial for forensic analysis.
• Antiforensic techniques aim to conceal manipulation fingerprints.
• Applying antiforensics can introduce distortion or increase data size.

Purpose of the Study:

• To characterize the 3D tradeoff between concealability, data rate, and distortion in antiforensics.
• To measure antiforensic attack effectiveness using a defined concealability metric.
• To examine this tradeoff in the context of double JPEG compression.

Main Methods:

• Defining and measuring signal concealability.
• Proposing flexible antiforensic dither for variable antiforensic strength.
• Developing an antiforensic transcoder for efficient processing.
• Simulating double JPEG compression with antiforensic modifications.

Main Results:

• Antiforensics can increase concealability and decrease data rate with a lower secondary JPEG quality factor.
• Higher secondary quality factors can achieve similar concealability and distortion at higher data rates.
• Lower secondary quality factors are incentivized for better rate-distortion-concealability balance.

Conclusions:

• The study quantifies the concealability-rate-distortion tradeoff in antiforensic JPEG compression.
• Flexible antiforensic dither and an efficient transcoder are proposed.
• Results indicate a strategic advantage in using lower secondary quality factors for antiforensic JPEG recompression.