[sexmonad]

The obvious solution for this would be for Android to expose "derive random numbers from image frame" as a permission. But this is unnecessary, because they can just seed /dev/random from this source at boot (or if the device is unseeded).

That said, mobile devices really aren't lacking in entropy sources. With all the radios and sensors in a modern smartphone, why do they need additional methods to generate random numbers?

For information security purposes, a cryptographically secure PRNG is typically at least as secure as the encryption algorithms that it protects.