/dev/random vs. /dev/urandom

[sans-hubris]

What's the difference between the two?

[Bradmont]

/dev/urandom spews out pseudorandom stuff as fast as it can, /dev/random collects system entropy from things like mouse movements and keystrokes. /dev/random is the much more random (and hence more secure) of the two.

[Strike]

Interesting article on the state of /dev/random currently - http://lwn.net/Articles/8228/

[jemfinch]

/dev/urandom injects entropy from the entropy pool into its pseudorandom generator when it has it, so it's generally a better source of more randomness than a plain old userspace generator.

Jeremy