SSL certificate for FTPS, is it the same as for HTTPS?

Solution 1:

Both FTPS and HTTPS use the same basic kind of certificate (SSL server certificate). However, depending on your software you may need it in a different format, such as pkcs8 instead of x509. There are ways to convert between those formats (openssl command-line stuff, mostly). Odds are high that clients are using the same libraries for the SSL portions of FTPS as for HTTPS; same for the servers.

I'm not doing any FTPS, but I can tell you that we use the exact same formats of certificates for HTTPS, IMAPS, IMAP+TLS, SMTP+TLS, LDAPS, LDAP+TLS, etc...

Solution 2:

As far as I know you use exactly the same type of SSL certificate (a server certificate, actually). Of course the certificate will have to be issued for the correct hostname of your FTP server.

You don't need a certificate from a "root certification authority" (the ones that come preinstalled on every system) unless you need to use the established PKI to prove your identity - ie. if you use it for internal use and check the certificate fingerprint to prove identity, there's no need for an external CA, and the certificate will then enable you to encrypt traffic anyway.