Protecting the monetary value of funds held in a central bank digital currency (CBDC) wallet on a smartphone requires a trusted application (TA) on the device that prohibits double spending. Hardware-based secure elements (SE) can hold TAs (called applets when on an SE), and most smartphones have embedded SEs. However, applets can be placed on a SE only with participation of the device manufacturer. The European Central Bank, which is interested in issuing a CBDC, recently requested feedback from manufacturers on how to deploy applets on their devices. The payment card industry hit this ...