Secure fragile digital watermarking technique for image authentication

We present a new fragile digital watermarking technique that can be used as a digital signature for data authentication. The technique presented is blind, efficient, secure and can detect and locate minor tampering applied to the image pixels. The technique is suitable for certain classes of image formats such as gif, tif or bitmap images. The digital signature is inserted by decorrelating the image samples in the spatial domain, then embedding the watermark in the transform domain of the decorrelated image. The mark is embedded using quantization and modulo arithmetic techniques with a small quantization step size. Any tampering with the image will create errors in the embedded bits, which can be easily detected