Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. https://crt.sh/?q=example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
I would like to know if it is possible to add custom data to TLS certificate? Let’s say I want to create a new CNAME blog.sridharg.org and have a TLS certificate issued by letsencrypt. Is it possible to include custom data to the certificate that also gets signed by letsencrypt? Or will letsencrypt filter out any custom data?