> dedicated machines for each application of each customer. I don't think you don't need to go this far. You can probably get away with circuit switching small

> dedicated machines for each application of each customer. I don't think you don't need to go this far. You can probably get away with circuit switching small blocks of hardware, and fully resetting them between handovers. Although you'd have to ensure sufficient randomisation / granularity to destroy side channels in the switching logic.