Information Hiding techniques are much researched in the context of watermarking or fingerprinting images and sound files, mainly as a means of copyright protection and piracy prevention/detection. Those mediums offer a significant amount of redundancy, thus lending themselves to the implementation of robust IH systems. Executables however do not offer such amounts of redundancy, and have thus far proven to be a difficult and rarely used medium for steganographic and other IH purposes. The aim of this talk is to be an introduction to IH, with a thorough coverage of state of the art techniques for embedding into binaries. Hydan, a tool for performing such embeddings in machine code, will be presented. In addition to typical IH uses [steganography, watermarking], the tool and techniques shown can be used in anti-reverse engineering, trusted application execution, frustrate some buffer overflow attacks, and as an engine for metamorphic viruses. An interesting effect of the tool is that the executable remains the same size before and after embedding, while of course remaining functionally equivalent.