OAuth

OAuth (short for open authorization) is an open standard for access delegation, commonly used as a way for internet users to grant websites or applications access to their information on other websites but without giving them the passwords.

Generally, the OAuth protocol provides a way for resource owners to provide a client application with secure delegated access to server resources.
— Wikipedia

OAuth - protocol to share sensitive data across systems.

OAuth’s protocol gives ability one service (my) access rights to read user’s data from another service (his) without sharing user’s password.

oauth.excalidraw

Oauth flow