[Cryptography] randomness +- entropy

Kent Borg kentborg at borg.org
Wed Nov 6 07:59:11 EST 2013


On 11/05/2013 06:09 PM, Theodore Ts'o wrote:
> And if I made /dev/urandom reads block until the pool was initialized, 
> I suspect that product managers would just tell the engineers to patch 
> out the check, as opposed to doing something intelligent

I still suggest adding a *mechanism* to block urandom before it has any 
entropy.  And if you can sneak in defaults that mostly no one notices 
but still help many...cool.

Those who don't like such a change, those who look deep enough to notice 
the change, can set their defaults to something suitable for them.  
(Leave helpful comments in the code for those who might find editing a 
couple constants in their private kernel sources easier than managing 
custom kernel parameters.)

But please add a mechanism as soon as possible, even if it is defaulted 
to off.


RNGs should try very hard to not fail silently and emit bad data.


-kb



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