Translation-based steganography

This paper investigates systems that steganographically embed information in the “noise” created by automatic translation of natural language documents. The main thrust of the work focuses on two problems - generation of plausible steganographic texts, and avoiding transmission of the original source for stego objects. Because the inherent redundancy of natural language creates plenty of room for variation in translation, machine translation is ideal for steganographic applications. We describe the design and implementation of a scheme for hiding information in translated natural language text and present experimental results using the implemented system. While the initial work in this vein required the presence of both the source and the translation, the system detailed in this paper requires only the translated text for recovering the hidden message, increasing security and improving resource usage. These improvements occur not only because the source text is no longer available to the adversary, but also because a broader repertoire of defenses (such as mixing human and machine translation) can now be used.