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In batch steganography, the sender distributes the secret payload among multiple images from a “bag” to decrease the chance of being caught. Recent work on this topic described an experimentally discovered phenomenon, which we call the “bag gain”: for fixed communication rate, pooled detectors experience a decrease in statistical detectability for initially increasing bag sizes, providing an opportunity for the sender to gain in security. The bag gain phenomenon is universal in the sense of manifesting under a wide spectrum of conditions. In this paper, we explain this experimental observation by adopting a statistical model of detector response. Despite the simplicity of the model, it does capture observed trends in detectability as a function of the bag size, the rate, and cover source properties. Additionally, and surprisingly, the model predicts that in certain cover sources the sender should avoid bag sizes that are too small as this can lead to a bag loss.
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This content will become publicly available on December 2, 2025
How to Form Bags in Batch Steganography
In batch steganography, the sender spreads the secret payload among multiple cover images forming a bag. The question investigated in this paper is how many and what kind of images the sender should select for her bag. We show that by forming bags with a bias towards selecting images that are more difficult to steganalyze, the sender can either lower the probability of being detected or save on bandwidth by sending a smaller bag. These improvements can be quite substantial. Our study begins with theoretical reasoning within a suitably simplified model. The findings are confirmed on experiments with real images and modern steganographic and steganalysis techniques.
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- Award ID(s):
- 2324991
- PAR ID:
- 10621661
- Publisher / Repository:
- IEEE
- Date Published:
- ISSN:
- 1081-0688
- ISBN:
- 979-8-3503-6442-2
- Page Range / eLocation ID:
- 1 to 6
- Subject(s) / Keyword(s):
- Batch steganography pooled steganalysis source biasing forming bags bias gain bandwidth savings
- Format(s):
- Medium: X
- Location:
- Rome, Italy
- Sponsoring Org:
- National Science Foundation
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