How is OAuth 2 different from OAuth 1?

In very simple terms, can someone explain the difference between OAuth 2 and OAuth 1?

Is OAuth 1 obsolete now? Should we be implementing OAuth 2? I don't see many implementations of OAuth 2; most are still using OAuth 1, which makes me doubt OAuth 2 is ready to use. Is it?

Solution 1:

Eran Hammer-Lahav has done an excellent job in explaining the majority of the differences in his article Introducing OAuth 2.0. To summarize, here are the key differences:

More OAuth Flows to allow better support for non-browser based applications. This is a main criticism against OAuth from client applications that were not browser based. For example, in OAuth 1.0, desktop applications or mobile phone applications had to direct the user to open their browser to the desired service, authenticate with the service, and copy the token from the service back to the application. The main criticism here is against the user experience. With OAuth 2.0, there are now new ways for an application to get authorization for a user.

OAuth 2.0 no longer requires client applications to have cryptography. This hearkens back to the old Twitter Auth API, which didn't require the application to HMAC hash tokens and request strings. With OAuth 2.0, the application can make a request using only the issued token over HTTPS.

OAuth 2.0 signatures are much less complicated. No more special parsing, sorting, or encoding.

OAuth 2.0 Access tokens are "short-lived". Typically, OAuth 1.0 Access tokens could be stored for a year or more (Twitter never let them expire). OAuth 2.0 has the notion of refresh tokens. While I'm not entirely sure what these are, my guess is that your access tokens can be short lived (i.e. session based) while your refresh tokens can be "life time". You'd use a refresh token to acquire a new access token rather than have the user re-authorize your application.

Finally, OAuth 2.0 is meant to have a clean separation of roles between the server responsible for handling OAuth requests and the server handling user authorization. More information about that is detailed in the aforementioned article.

Solution 2:

I see great answers up here but what I miss were some diagrams and since I had to work with Spring Framework I came across their explanation.

I find the following diagrams very useful. They illustrate the difference in communication between parties with OAuth2 and OAuth1.

OAuth 2

enter image description here

OAuth 1

enter image description here

Solution 3:

The previous explanations are all overly detailed and complicated IMO. Put simply, OAuth 2 delegates security to the HTTPS protocol. OAuth 1 did not require this and consequentially had alternative methods to deal with various attacks. These methods required the application to engage in certain security protocols which are complicated and can be difficult to implement. Therefore, it is simpler to just rely on the HTTPS for security so that application developers dont need to worry about it.

As to your other questions, the answer depends. Some services dont want to require the use of HTTPS, were developed before OAuth 2, or have some other requirement which may prevent them from using OAuth 2. Furthermore, there has been a lot of debate about the OAuth 2 protocol itself. As you can see, Facebook, Google, and a few others each have slightly varying versions of the protocols implemented. So some people stick with OAuth 1 because it is more uniform across the different platforms. Recently, the OAuth 2 protocol has been finalized but we have yet to see how its adoption will take.