BOX is a system which consists of 1 Mac as signature machine, >3 iPhone to install operation app, 2 cloud/inhouse servers to run the logic. What it offers is a business wallet, which provides extra functions compared with private one -- 1) shared permission for the private key, no one will know the exact private key, no one individually can control the key; 2) hierarchical approval template is defined by manager and confirmed by private key share holders.