ZeroDay is a blog on the Deep Web where an unknown hacker discusses ways to get around some of the most common security systems. They claim that a phone app they developed, The Mobile R.A.T, can hack into any smart phone and retrieve any data you want from it. Website navigation can be difficult because there are five subpages here and they're all decently long.
A Red Room Key can be found on any subpage in one of the paragraphes of text, already visible, or being triggered by something like the headlines or the blue text under the headlines. It may also be triggered by clicking on [j++] in the picture.
This site also has a question on The Gatekeeper: "At which day did the Mobile Rat arrive on zeroDay?" - Answer: 042116