1. Letsencrypt/ACME

https://letsencrypt.org/docs/client-options/

ACMEプロトコルの仕組み https://http2.try-and-test.net/letsencrypt.html#acme_protocol

1.1. Challenge Types

https://letsencrypt.org/docs/challenge-types/

1.2. ACME Client Implementations

Recommended: Certbot /certbot

ACME v2 Compatible Clients

Certbot (Certbot >= 0.22.0)

acmebot https://github.com/plinss/acmebot

../acme.sh ../dehydrated ../certbot-auto _acme_challenge