For the past couple of years I have used ZeroSSL as the interface to LetsEncrypt to generate my tri-monthly certificate and then uploaded it to GoDaddy via cPanel (since GoDaddy does not directly support LE). It’s worked fine.
ZeroSSL now, though, requires a paid account to generate a certificate covering all my more-than-3 domains. The nice Wizard is gone. So I plan to switch to GetHTTPSForFree as my interface to LE.
On GetHTTPForFree, I am first asked to input the email address and public key used for LE. I don’t have the public key as far as I know. From my repeated interactions via ZeroSSL, I have my LE-account-key (which curiously starts with a header saying BEGIN RSA PRIVATE KEY), my private key (which also starts with a BEGIN RSA PRIVATE KEY header), my CSR certificate request (which automatically incorporates all my domains), and of course my final domains certificate updated each 90 days.
I thought perhaps the LE account key was the public key. But GetHTTPSForFree gives me an error when I paste that in, even when I change the header to “BEGIN PUBLIC KEY” as it seems to expect. I don’t have and don’t recall ever seeing a file with a BEGIN PUBLIC KEY header.
But, hey, it’s supposed to be public, right? So I figure there is some way to find it.
I have spent some time searching through the archives here (and elsewhere online) for an answer. No luck so far.