Oauth

An open protocol to allow secure authorization in a simple and standard method from web, mobile and desktop applications

OAuth (Open Authorization[1][2]) 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.[3][4] This mechanism is used by companies such as Amazon,[5] Google, Facebook, Microsoft and Twitter to permit the users to share information about their accounts with third-party applications or websites.