Inconvenient Message Detection



Steganography that requires computing effort. Steganography is the idea of hiding data in the unimportant bits of an image. This is an old idea. The new twist is that with ‘Inconvenient Message Detection’ (IMD) that data can only be found if the decoder does an amount of computational work that’s decided by the encoder.

Let’s look at how this solved our problem: If some people use IMD, it makes every image suspect. When a mass-observer wants to see what communication is going on, they must use compute power to check every image. Furthermore, because the compute effort needed to find an image is set by the encoder, it is uncertain to the mass-observer; they never knows for certain if they’ve worked hard enough. By contrast, the intended recipient of a message presumably got the single datum that a message exists in some public image and will put in as much compute effort as is needed to find the data in that single image. Having every image on the internet be a potential carrier of secrets makes the mass observation of communication meta-data expensive and uncertain.

Furthermore, even a individual under direct observation can increase their protection with IMD. An individual may own thousands of images of which only one contains an secret. Until the secret is found by an observer, the individual has plausible denyability of the secret’s existence. The observer may even give up before spending the necessary compute effort to find it. This increases their resistance to coercion.