[Cryptography] The Crypto Pi

ianG iang at iang.org
Mon Jan 26 08:12:29 EST 2015

On 25/01/2015 16:35 pm, Ralf Senderek wrote:

> When I read bytes from /dev/random with dd and immediately check this
> file again, n bits are missing as a result of the read operation.
> So, IMHO, the whole system now has less entropy to feed to /dev/random.
> Am I wrong, when I assume that if the content of entropy_avail drops to
> zero, /dev/random is supposed to block?

Once upon a time, it might have meant that.  Now it doesn't.

What it "means" is more to do with whatever is implemented by the 
primary unix system you are using, and as it happens, Linux and BSD do 
differently.  So meaning is out the window, we're back to implementation.

My advice:  applications should use /dev/urandom.


ps; more long-winded stuff here

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