This book constitutes the thoroughly refereed post-proceedings of the 12th International Workshop on Digital-Forensics and Watermarking, IWDW 2013, held in Auckland, New Zealand, during October 2013. The 24 full and 13 poster papers, presented together with 2 abstracts, were carefully reviewed and selected from 55 submissions. The papers are organized in topical sections on steganography and steganalysis; visual cryptography; reversible data hiding; forensics; watermarking; anonymizing and plate recognition.