What is a "CSR" and how do I get one?

CSR is a Certificate Signing Request

Basic overview

This file contains pieces of information about your cert and your public key.

It is used by the CA or Certification Authority (here : CAcert Inc.) to sign your cert (and obviously the info included in the cert).

The CA do not need the private key you have generated. You keep your private key secret.

The CA uses this CSR file to grab the info, verifying the info from your account and then generate the real certificate that you ( and your services) will use during secure communications with clients (HTTPS,SSL,POP3/SSL, etc.) and servers.

(based on Bruno ideas on CAcert support mailing list)

More info

You can read SubmitCsr and also see http://wiki.cacert.org/wiki/WebServers?action=highlight&value=CSR

if you do not understand CSRs so well or while you don't know what they are simply are, follow thoses guides:

 https://www.cacert.org/help.php?id=3 

 https://www.cacert.org/help.php?id=4 

Official OpenSSL stuff

You can get some more info reading OpenSSL documentation.

http://www.openssl.org/docs/