This book constitutes the thoroughly refereed post-proceedings of the Third International Workshop on Digital Watermarking, IWDW 2004, held in Seoul, Korea in October/November 2004.

The 22 revised full papers presented together with 3 invited papers were carefully selected from over 60 submissions during two rounds of reviewing and improvement. The papers are organized in topical sections on systems, theory, authentication and steganography, cryptography, and methods.