This book constitutes the thoroughly refereed post-proceedings of the 9th International Workshop on Information Hiding, IH 2007, held in Saint Malo, France, in June 2007.

The 25 revised full papers presented were carefully reviewed and selected from 105 submissions. The papers are organized in topical sections on new steganographic schemes, watermarking schemes, computer security, steganography and code theory, watermarking security, steganalysis, watermarking and re-synchronization, fingerprinting, forensics, and steganalysis.

This book explains how to measure the security of a watermarking scheme, how to design secure schemes but also how to attack popular watermarking schemes. This book gathers the most recent achievements in the field of watermarking security by considering both parts of this cat and mouse game. This book is useful to industrial practitioners who would like to increase the security of their watermarking applications and for academics to quickly master this fascinating domain.