One technical solution to this is encrypting the content of ram, using keys that cannot leave the processor. It's called TREZOR. Sorry no link, I'm on mobile .

One technical solution to this is encrypting the content of ram, using keys that cannot leave the processor. It's called TREZOR. Sorry no link, I'm on mobile . It doesn't work well with current phones but it should work well with cortex-a15 chips (assuming they won't be back doored against this, which is pretty hard to assume. But as far as I know, there isn't a realistic solution to back doored processors ).