Since the mid 1990s, data hiding has been proposed as an enabling technology for securing multimedia communication, and is now used in various applications including broadcast monitoring, movie fingerprinting, steganography, video indexing and retrieval, and image authentication. Data hiding and cryptographic techniques are often combined to complement each other, thus triggering the development of a new research field of multimedia security. Besides, two related disciplines, steganalysis and data forensics, are increasingly attracting researchers and becoming another new research field of multimedia security. This journal, LNCS Transactions on Data Hiding and Multimedia Security, aims to be a forum for all researchers in these emerging fields, publishing both original and archival research results. This second issue contains five papers dealing with a wide range of topics related to multimedia security. The first paper introduces Fingercasting, which allows joint fingerprinting and decryption of broadcast messages. The second paper presents an estimation attack on content-based video fingerprinting. The third proposes a statistics and spatiality-based feature distance measure for error resilient image authentication. The fourth paper reports on LTSB steganalysis. Finally, the fifth paper surveys various blind and robust watermarking schemes for 3D shapes.