Hi - the 'vault' concept is simply to help understanding. Every ARM and Intel chip ships with a second isolated micro-chip inside it that is independent from the operating system of the phone (or other device). However, this is not widely know as you would not normally come into contact with it. Rivetz makes use of this secure area to remain uncompromised by the daily and highly insecure functions of the device. The device owener can do what they like with the contents of the operating system, download apps or whatever, but Rivetz is securely isolated from this in a 'vault-like' manner.