If you're anything like us, you've already made millions of dollars on Bitcoin. But how to keep it safe from loved ones, co-workers and other people we don't trust? Sound Wallet promises to keep your private access keys secure as encrypted audio, either on CDs or 7-inch vinyl, presumably just because it can. The system isn't limited to Bitcoin - other less popular brands of cryptocurrency can also benefit from the nostalgia-tinged protection. Your encrypted login key is converted into a sound file less than a minute long, and while it'll sound like white noise to anyone listening, a spectroscope app (yeah, you're going to need your smartphone), will be able to pluck the appropriate information out of the track.