On ShapeShift KeepKey devices, a side channel for the row-based OLED display was found

On ShapeShift KeepKey devices, a side channel for the row-based OLED display was found. The power consumption of each row-based display cycle depends on the number of illuminated pixels, allowing a partial recovery of display contents. For example, a hardware implant in the USB cable might be able to leverage this behavior to recover secret data shown on the display. In other words, the side channel is relevant only if the attacker has enough control over the device's USB connection to make power-consumption measurements at a time when secret data is displayed. The side channel is not relevant in other circumstances, such as a stolen device that is not currently displaying secret data. NOTE: the vendor's position is that there is "insignificant risk.