Token based implementation in webapi to secure endpoints

Question

I am having a web application with web service and client will register their application using my web application.

Now client will have application of type

Answer 1

From “7.1. Access Token Representation” in “Full-Scratch Implementor of OAuth and OpenID Connect Talks About Findings” :

How should an access token be represented? There are two major ways.

1. As a meaningless random string. Information associated with an access token is stored in a database table behind an authorization server.

2. As a self-contained string which is a result of encoding access token information by base64url or something similar.

Pros and cons of these two ways are described in the blog.

If access tokens are random strings, pieces of information associated with the access tokens (user ID, client ID, scopes, lifetime, etc.) are stored in a database which is managed by the authorization server which have issued the access tokens.

Whenever a resource server which exposes APIs accepts an API call from a client application, the resource server has to get the information about the access token in some way or other.

If the resource server can access the database managed by the authorization server (in other words, if the resource server and the authorization server shares the database), the resource server can get the information about the access token from the database directly.

Otherwise, the resource server has to make an API call to the authorization server to get the information. In this case, it can be expected that the authorization server exposes an API which complies with RFC 7662 (OAuth 2.0 Token Introspection). Note that some implementations may provide a more developer-friendly API than RFC 7662 (e.g. “4. Introspection Access Token”).

Anyway, your resource server doesn't necessarily have to make a DB call (or an introspection API call to the authorization server) every time if the server caches information about access tokens in a memory cache or somewhere else appropriate.

BTW, what you need when you want to protect APIs is access tokens. Therefore, your system doesn't have to support OpenID Connect which is a specification as to how to request and issue ID tokens. You may be confused because a server which supports OpenID Connect can issue access tokens, too, in addition to ID tokens. See “Diagrams of All The OpenID Connect Flows” to understand what a server which supports OpenID Connect issues.

Finally, identity management, user authentication, and OAuth 2.0 & OpenID Connect don't necessarily have to be implemented in a monolithic way. See “New Architecture of OAuth 2.0 and OpenID Connect Implementation” for details.