Applying Statistics Ogive to Semi-Fragile Authentication of JPEG Images for Communication System

Semi-fragile image authentication methods are robust to JPEG images, but are fragile to other malicious manipulations. This paper presents a novel digital signature scheme that adopts statistic Ogive analysis in quantized discrete cosine transform (DCT) coefficients to construct a feature code for image authentication. The lower bound sensitivity of fragility can be determined by a predetermined degree of fragility corresponding to an acceptable JPEG compression quality factor. The degree of fragility can be easily adjusted by simply controlling a fragile degree factor (FDF). This paper analyzes how to choose FDF and the critical image feature properties. Experimental results indicate the effectiveness of the proposed method.