If you want to enable Cyrus’ TLS/SSL facilities, you have to create a certificate first. This requires an OpenSSL installation.
openssl req -new -nodes -out req.pem -keyout key.pem
openssl rsa -in key.pem -out new.key.pem
openssl x509 -in req.pem -out ca-cert -req
-signkey new.key.pem -days 999
mkdir /var/imap
cp new.key.pem /var/imap/server.pem
rm new.key.pem
cat ca-cert >> /var/imap/server.pem
chown cyrus:mail /var/imap/server.pem
chmod 600 /var/imap/server.pem # Your key should be protected
echo tls_ca_file: /var/imap/server.pem >> /etc/imapd.conf
echo tls_cert_file: /var/imap/server.pem >> /etc/imapd.conf
echo tls_key_file: /var/imap/server.pem >> /etc/imapd.conf