You can re-run the script that generates the default certificates on new installations as follows:
/usr/lib/inithooks/firstboot.d/15regen-sslcert
If you look at the source of the above script (or execute it with --help), you'll see that the default values can be tweaked. For example, if you want to change the default amount of bits (1024), prepend the script with BITS=2048
blog post for reference + inithook
Take a look at this blog post for reference: http://www.turnkeylinux.org/blog/ssl-certificates
You can re-run the script that generates the default certificates on new installations as follows:
If you look at the source of the above script (or execute it with --help), you'll see that the default values can be tweaked. For example, if you want to change the default amount of bits (1024), prepend the script with BITS=2048
Hope the above helps.