Yes this is possible. The only verification is that you are able to react to certain HTTP requests sent to port 80 on your domain.<p><a href="https:&#x2F;&#x2F;community.letsencrypt.org&#x2F;t&#x2F;possible-to-issue-certificates-for-customers-subdomains&#x2F;1504" rel="nofollow">https:&#x2F;&#x2F;community.letsencrypt.org&#x2F;t&#x2F;possible-to-issue-certif...</a>