Due to an influx of spam, we have had to temporarily disable account registrations. Please write an email to accountsupport@archlinux.org, with your desired username, if you want to get access. Sorry for the inconvenience.
certbot switched to ECDSA by default about two years ago, following recommended practices.
We are currently using RSA with 4096 bits, which is extremely slow to sign. Using ECDSA should give us a nice speedup.