StegNmark: A joint stego-watermark approach for early tamper detection

Abstract

The exponential advancement in the fields of computer networks and multimedia signal processing has resulted in easy availability of digital multimedia content over the internet nowadays. However, this advancement has given rise to many challenges in terms of information security and content authentication that need to be taken care of. A novel technique based on combination of Steganography and Fragile Watermarking called as StegNmark for content authentication utilizing the concept of early tamper detection has been proposed in this chapter. StegNmark is a spatial-domain data hiding technique which is capable of early tamper detection of a given stego-image. The early detection could be quite useful in situations where (data extraction) time factor plays a critical role like data extraction indicating a warfare plan to attack the enemy. This is achieved by embedding a fragile watermark of about 1% of total payload using bit interleaving in the cover medium. The comparatively lower payload watermark (compared to secret data embedded in the StegNmark) is first extracted for authentication purpose. If the watermark detected is same as that used at the transmitter, then only secret data is extracted from the stegomarked medium. Experimental results reveal that besides providing high-quality stego-images the proposed system is capable of saving appreciable amount of extraction time due to early tamper detection.