Recently, the side-channel attack "Screaming Channel" was described in a paper (http://s3.eurecom.fr/tools/screaming_channels/). The authors demonstrate a remote, passive, side-channel attack on nrf52 that allows data to be compromised if the processor handles sensitive data at the same time as the chip is transmitting over the radio.
What is a good countermeasure to this attack?
The paper (Section 7.3) mentions one promising countermeasure; "to ensure that the radio is never active in transmit mode during sensitive computations". However, is this possible with the SoftDevice approach. Do I, as a developer, have complete control over when the radio is transmitting or not? In practice, how could this countermeasure be programmed?