I know that random number generators on computers are only pseudo-random, but are the PRNGs on Live Boot USB or DVDs even less random? Is there a way to seed them after booting?

Specifically curious about Xubuntu 14 on USB.


A running linux system typically has four categories of entropy sources to draw from. They are environmental (temperature sensors, disks), user (mouse, keyboard), time (the clock), and network. Some computers do not have temperature sensors, or physical drives (solid state drives do not count because they have no moving parts to gather entropy from), the clock is predictable, the network can be attacked if it is the only source of entropy. Chances are if you do stiff with the computer before needing randomness, the computer will get enough from you, but the more entropy sources your computer has the better. You can inject randomness directly into the kernel, but I can't remember how off the top of my head. I have been drooling over http://ubld.it/products/truerng-hardware-random-number-generator/. I think I saw something on their documentation related.

One that is really bad: network booting a diskless machine. no user interaction yet, network and clock are both week here, and nothing else is available yet.

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