HTTPS support on Pico!

I have been playing around with Node.js and I came across this..... https://nodejs.org/api/https.html

key: Private key to use for SSL. Default null.
passphrase: A string of passphrase for the private key or pfx. Default null.
cert: Public x509 certificate to use. Default null.
ca: A string, Buffer or array of strings or Buffers of trusted certificates in PEM format. If this is omitted several well known "root" CAs will be used, like VeriSign. These are used to authorize connections.

I built a client app.js and have been using both POST and GET to send information into a Google Form or direct to spreadsheet with these all left at default. So to answer your question it appears that the only thing needed is the CA.