Stirling Transform based Color Image Authentication

In this paper, a fragile watermarking technique based on Stirling transform (ST) has been proposed to authenticate color images (STCIA). The pixel components of the cover/carrier image are adjusted prior to embedding, if necessary. Stirling transform (ST) is used to convert each pair of pixel components into transformed pair in row major order. Two bits of the watermark starting from the least bit position are embedded. A post-embedding adjustment has also been incorporated to keep the embedded components closest to the original without hampering the fabricated watermark bits. Inverse Stirling transform (IST) is appli ed on each adjusted pair to obtain the watermarked image. The recipient extracts the whole watermark through reverse procedure which in turn may be verified for authentication by ensuring the integrity of the re-generated message digest. Experimental results conforms that the proposed technique has been improvised in terms of payload and PSNR over existing techniques [13,14].