On 5/26/2023 4:38 AM, J.Witvliet--- via users wrote:
-----Original Message----- From: Jeffrey Walton <noloader@xxxxxxxxx> Sent: Friday, May 26, 2023 4:20 AM To: Community support for Fedora users <users@xxxxxxxxxxxxxxxxxxxxxxx> Subject: Re: randomization On Thu, May 25, 2023 at 9:18 PM Bill Cunningham <bill.cu1234@xxxxxxxxx> wrote:How would you access randomization at the system level? No via srand or rand, but the randomization the system offers through /dev/random. Would this be a fedora level system call ? I intend to take a 512 or 1024, for example, size chunk and fill that with system randomization. Not what you get with srand and rand I believe they are inferior to system randomization.You should use /dev/urandom nowadays, not /dev/random. According to Theodore Ts'o on the Linux Kernel Crypto mailing list, /dev/random has been deprecated for a decade. From Re: [RFC PATCH v12 3/4] Linux Random Number Generator:[1] Practically no one uses /dev/random. It's essentially a deprecated interface; the primary interfaces that have been recommended for well over a decade is /dev/urandom, and now, getrandom(2). There is a difference between random and urandom, mainly the "quality of it randomness" Especially when doing crypto related tasks (VPNs) on a virtual machine, you might find that your entropy pool is small and easiliy depleted. In such cases, reading from /dev/random will block (bad), but reading from /dev/urandom get bad quality (perhaps even worse) However, there are ways to replenish the entropy buffer... That leads me to the idea of haveged. I have my system set up to ctivate it manually. My question was about a C related function originally, that would provide powerful randomness, but this is very interesting. Has anyone actually used haveged?
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