In this paper

we discuss several problems on fragile watermarking

which is used to ensure the credibility of multimedia. Firstly

we describe some main properties that an efficient fragile watermarking scheme should have. And then we discuss the differences between robust watermarking and fragile watermarking algorithms

which are important for us to develop efficient fragile watermarking scheme. Thirdly

a simple application framework for fragile watermarking

which is called trustworthy digital camera

is proposed. This fragile watermarking framework can be used for ensure facticity for images taken by digital camera. In the end

we present two approaches

pre processing and using integer transform

to solve round off error and overflow error problems for frequency domain fragile watermarking techniques. Experimental results show that these two approaches are efficient for improving other fragile watermarking algorithms.