This looks really cute, especially given the ability to "precompute" entropy before the process that needs it is running. An interface I'd rather see is one that allows a process to grab random bits that it can be sure are not correlated to bits that have been given to other processes. Since everything runs asynchronously with cron, you have no way of knowing how much time has elapsed since the last time the file was read or updated, and hence don't know how "fresh" the bits are. Also, /etc/noiz is an attractive target on multi-user machines.... So I'd rather see a /dev/noise, although a portable implementation of somthing like that is out of the question now that there are 10 gazillion unix vendors. Perhaps a more reasonable implementation would be a tcp or rpc service that processes can query to get random bits, where the server delays responding until it can guarantee that its state is sufficiently decorrelated from previous responses. Because you can "bank up" entropy during idle periods, most requests could probably be served without delay, making this technique a real advantage over just implementing the same functions in a library called directly. (Since good randomness is still rather expensive even when you can store it up, and useless when sent over a network, you'd probably want the noise server to refuse requests from outside the local machine.) Anyway, I'm looking forward to playing with it. It's a very nice idea. -matt