[cryptography] urandom vs random

Patrick Pelletier code at funwithsoftware.org
Fri Aug 23 00:54:36 EDT 2013


On 8/22/13 9:40 AM, Nico Williams wrote:

> My suggestion is /dev/urandomN where N is one of 128, 192, or 256, and
> represents the minimum entropy estimate of HW RNG inputs to date to
> /dev/urandomN's pool.  If the pool hasn't received that much entropy
> at read(2) time, then block, else never block and just keep stretching
> that entropy and accepting new entropy as necessary.

That sounds like the perfect interface!  The existing dichotomy between 
random and urandom (on Linux) is horrible, and it's nice to be able to 
specify how much entropy you are in need of.

--Patrick



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