https://en.wikipedia.org/wiki/Basic_access_authentication https://docs.microsoft.com/en-us/powerapps/developer/common-data-service/authenticate-oauth https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-auth-code-flow#request-an-access-token https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-auth-code-flow#request-an-access-token