I'm always searching for a how-to for creating a ssl-certificate.
Now I'm describing here one way.
Creating private keyfile:
without passphrase:
openssl genrsa -out privkey.pem 2048
with passphrase and good encryption (for other encryption algorithm see manpage):
openssl genrsa -aes256 -out privkey.pem 2048
Creating CA-Certificate:
openssl req -new -x509 -key privkey.pem -out cacert.pem -days 1095
Creating for pure-ftpd:
openssl req -x509 -nodes -newkey rsa:1024 -keyout pure-ftpd.pem -out pure-ftpd.pem