4 ms·
From the manpage of /dev/random "If a seed file is saved across reboots as recommended below (all major Linux distributions have done this since 2000 at least)
by gizmo686 14y ago
From the manpage of /dev/random
"If a seed file is saved across reboots as recommended below (all major Linux distributions have done this since 2000 at least), the output is cryptographically secure against attackers without local root access as soon as it is reloaded in the boot sequence, and perfectly adequate for network encryption session keys. Since reads from /dev/random may block, users will usually want to open it in nonblocking mode (or perform a read with timeout), and provide some sort of user notification if the desired entropy is not immediately available."
- marshray 14y agoOnly if the seed file was was generated by a secure kernel during a clean shutdown and kept secret during that whole time. There's a lot to go wrong there, especially if you're an embedded system running on flash. I also seem to recall host keys being generated on first boot. Perhaps some installers are smart enough to prime that seed file.