Authentication and authorization are key security aspects when working with RESTful APIs. They provide access control to resources and protection against unauthorized use. Modern web applications often use standards such as OAuth 2.0 and JWT (JSON Web Token) for secure user authentication and authorization. In this article, we will look at how these technologies work, their features, and advantages and disadvantages.
What is authentication and authorization?
Authentication is the process of confirming a user’s authenticity, that is, verifying their identity. For example, when a user enters a username and password, the system must verify that this data is correct and belongs to the real user.
Authorization is the process of granting or restricting access to certain resources or actions based on a user’s rights. For example, a regular user may only have access to view their data, while an administrator may have access to all system data.
OAuth 2.0: the foundation for secure authentication
OAuth 2.0 is a standard protocol for authentication that provides access tokens to work with resources on behalf of a user. This protocol is widely used in web applications to allow third-party applications to securely interact with resources without passing logins and passwords.
How OAuth 2.0 works:
OAuth 2.0 uses a model where different roles are separated:
- A Client is an application that requests access to resources.
- Resource Server is the server that stores the user’s resources (such as APIs).
- Authorization Server – A server that validates the user and issues an access token.
- User (Resource Owner) – The resource owner who grants access authorization.
The main stages of OAuth 2.0:
Authorization Request: The client (e.g., mobile app) redirects the user to an authorization server where the user enters their login credentials (e.g., username and password).
Granting permissions: The user agrees to allow the app access to their resources (e.g., allow the app to access their email).
Obtaining an authorization code: After successful authentication, the authorization server sends the client a code that will be used to obtain a token.
Obtaining an access token: The client sends the code to the authorization server and receives an Access Token, which is used to work with the API.
Accessing Resources: The client uses the token to access the user’s resources on the resource server.
Types of tokens in OAuth 2.0:
Access Token: An access token used to make requests on behalf of the user. This token usually has a limited validity period.
Refresh Token: A token that allows a new Access Token to be obtained without re-authenticating the user. It is used for a long-term session.
Benefits of OAuth 2.0:
Security: OAuth 2.0 allows applications to work with users’ resources without asking them for logins and passwords.
Flexibility: Supports different types of clients (web applications, mobile applications, servers).
Multi-level authorization: Ability to grant access to only certain parts of resources.
Disadvantages of OAuth 2.0:
Configuration complexity: OAuth 2.0 requires configuring multiple components (clients, servers, tokens), which increases the complexity of implementation.
Token security: If an access token is compromised, an attacker can access user data.
JWT: A standard for data transfer
JSON Web Token (JWT) is a compact and secure format for transferring data between two parties in the form of tokens. JWT is often used to transfer user information after user authentication.
How JWT works:
JWT consists of three parts separated by dots:
Header: Contains information about the type of token and the encryption algorithm used (e.g., HMAC SHA256).
Payload: Contains encoded data (e.g., user ID, access rights, and token expiration date).
Signature: This is a digital signature to ensure that the data has not been altered. The signature is created using the secret key and algorithm specified in the header.