What are Bearer Tokens and token_type in OAuth 2?
I'm trying to implement the Resource Owner & Password Credentials flow from the OAuth 2 spec. I'm having trouble understanding the token_type value that gets sent back with a valid response. In the spec all the examples show "token_type":"example" but says it should be
token_type REQUIRED. The type of the token issued as described in Section 7.1. Value is case insensitive.
Can someone please explain this to me?
Answer
token_type is a parameter in Access Token generate call to Authorization server, which essentially represents how an access_token will be generated and presented for resource access calls.
You provide token_type in the access token generation call to an authorization server.
If you choose Bearer (default on most implementation), an access_token is generated and sent back to you. Bearer can be simply understood as "give access to the bearer of this token." One valid token and no question asked. On the other hand, if you choose Mac and sign_type (default hmac-sha-1 on most implementation), the access token is generated and kept as secret in Key Manager as an attribute, and an encrypted secret is sent back as access_token.
Yes, you can use your own implementation of token_type, but that might not make much sense as developers will need to follow your process rather than standard implementations of OAuth.