ACME
RFC 8555 Automatic Certificate Management Environment（自動証明書管理環境）
自動でTLSなどTLS用PKIのx.509証明書を更新する仕組み
RFC 8823 S/MIME拡張
RFC 9448 TNAuthList Profile of Automated Certificate Management Environment (ACME) Authority Token
RFC 9447 Automated Certificate Management Environment (ACME) Challenges Using an Authority Token
RFC 9444 Automated Certificate Management Environment (ACME) for Subdomains
RFC 9115 An Automatic Certificate Management Environment (ACME) Profile for Generating Delegated Certificates
RFC 8738 Automated Certificate Management Environment (ACME) IP Identifier Validation Extension
RFC 8659 DNS Certification Authority Authorization (CAA) Resource Record
RFC 6844 → 8659
https://datatracker.ietf.org/wg/acme/about/
JSON、JWSを利用する