ABSTRACT
This chapter discusses different types of watermarking attacks and available tools. It categorizes the various watermarking attack schemes into four classes: image-processing attacks, geometric transformation, cryptographic attacks, and protocol attacks. The chapter introduces image processing, geometric transformation, cryptographic attacks, and protocol attacks. It describes watermarking tools, and also presents an efficient block-based fragile watermarking system for tamper localization and recovery. Attackers of watermarked images can be classified as unintentional or intentional. Most digital watermarking methods are designed to be flexible only to uniform scaling. Many modern schemes use a template in the frequency domain to extract the watermark. A cryptographic attack attempts to circumvent the security of a cryptographic system by retrieving the key or exposing the plaintext in a code, cipher, or protocol. Protocol attacks intend to generate protocol ambiguity in the watermarking process. Holliman and Memon presented a counterfeiting attack on blockwise independent watermarking schemes.
