TCB13 , 7 months ago

Okay that’s fair but if your only concern is about “I do not want any public CA to know the domains and subdomains I use” you get around that.

Let’s Encrypt now allows for wildcard so you can probably do something like *.network.example.org and have an SSL certificate that will cover any subdomain under network.example.org (eg. host1.network.example.org). Or even better, get a wildcard like *.example.org and you’ll be done for everything.

I’m just suggesting this alternative because it would make your life way easier and potentially more secure without actually revealing internal subdomains to the CA.

Another option is to just issue certificates without a CA and accept them one at the time on each device. This won’t expose you to a possibly stolen CA PK and you’ll get notified if previously the accepted certificate of some host changes.

<span style="color:#323232;">openssl req -x509 -nodes -newkey rsa:2048 
</span><span style="color:#323232;">-subj "/CN=$DOMAIN_BASE/O=$ORG_NAME/OU=$ORG_UNIT_NAME/C=$COUNTRY" 
</span><span style="color:#323232;">-keyout $DOMAIN_BASE.key -out $DOMAIN_BASE.crt -days $OPT_days "${ALT_NAMES[@]}"
</span>