SSO & Single Sign On
单点登录
https://en.wikipedia.org/wiki/Single_sign-on
https://cloud.google.com/identity/sso/
大型 SSO 应用目录, 采用 SAML、OAuth 和 OpenID Connect (OIDC) 等行业标准的数千个预集成的应用。
https://auth0.com/docs/sso/current
https://auth0.com/learn/how-to-implement-single-sign-on/
