The OSN-Tagging scheme: Recoverable steganography for online social networks
Tayana Morkel · 2017
Online social networks (OSNs) offer the functionality of sharing information and images between users. The sharing of specifically images, offers a promising covert channel for secure and private communication by hiding information in images using steganography. However, many known steganography algorithms are not suitable for OSNs since the image processing that is performed when uploading an image modifies the image in such a way that the embedded information becomes irrecoverable. This paper proposes a steganography scheme that uses a variation of the Tagging watermarking algorithm (not to be confused with the Facebook concept of tagging) to embed a message in an image that can survive the image processing done by OSNs. The proposed OSN-Tagging scheme adjusts the brightness levels of certain areas of an image, thereby representing a message. Experimental results show that the tags and message embedded with the OSN-Tagging scheme can successfully be recovered after the image was uploaded to an OSN. Recommendations and considerations are made regarding tag size and brightness adjustment levels based on experimental results.