ABSTRACT
During the last two decades, the issue of enhancing privacy in transmitted data has attracted the attention of many researchers from dierent elds, and many complementary methods have been suggested in order to improve privacy. As more and more information is being transferred electronically, the issue of interest here is that if someone accesses all of the data, he or she has the potential to copy it and retransmit it to unauthorized parties. is is because of the nature of digital data, which is easily reproducible. Usually, this topic is covered together with image encryption, cryptography, or watermarking. e focus in this chapter is on the watermarking technique. is technique does not distort the image but embeds some hidden information, which is like a secret signature that can be accessed by authorized users before copying it or retransmitting it. Watermarking was rst used for copyright protection, but applications of watermarking have recently been expanded to content verication, authentication, covert communications, and information retrieval.
