Entropy in an enthalpic universe

Entropy in computers is the measure of the amount of randomness. Low power consumption devices tend to work poorly as encryption generation devices because of low entropy. During testing I found that the standard /dev/urandom device scored 180-200 at idle. While this is good for low power use not so good if using a VPN or running stream encryption.

The solution is to use a different algorithm that takes more of the typically unassociated activity of the board into effect.

HAVEGED in the apt debian repo provides such a tool. This will give you by default an entropy of 4096. I am unsure if there is a correct ratio but I tend to think that at least the double of the size of the key is good enough. You will find that random number generation for larger string is much quicker.