OAuth 2.0 Device Authorization Grant

看到「OAuth 2.0 Device Authorization Grant」這個變成 PROPOSED STANDARD 了,看了一下歷史是 2015 年年底的時候被提出來的,記得在前公司的時候有用這個 (當時還是 draft) 做智慧型電視上的 OAuth 認證:

The OAuth 2.0 device authorization grant is designed for Internet-connected devices that either lack a browser to perform a user-agent-based authorization or are input constrained to the extent that requiring the user to input text in order to authenticate during the authorization flow is impractical. It enables OAuth clients on such devices (like smart TVs, media consoles, digital picture frames, and printers) to obtain user authorization to access protected resources by using a user agent on a separate device.

因為這些裝置的輸入設備受限,照原來 OAuth 2.0 的方式授權,使用者體驗不會太好 (可以想像用遙控器登入 Google 或是 Facebook 帳號?),所以設計了替代的方案,讓使用者可以用手機授權 (比較常見的是透過 QR code),然後電視機再去取得 access token。