A device power supply includes an amplifier, a high output-side force terminal connected to the output of the amplifier, a high-output side sense terminal, and a first feedback circuit from the high output-side sense terminal to the input of the amplifier, where there is a first low-pass filter in between the amplifier output and the first feedback circuit. A method may comprise receiving, via one or more computing devices, a selected portion of content to redact in a first online meeting. The row direction and the first virtual linear lines L1 define an angle of 2-40 degrees, and the dummy wiring layers 32 are disposed in a manner to be located on the first virtual linear lines L1. The instructions implement an encryption function, which causes the private user data to be encrypted within the response data.