Explain HTTP authentication - GeeksforGeeks (2024)

We are in big doors to the digital era where comfort is the main driver. Enjoying all the convenience right from ordering merchandise and paying bills to get services while sitting on the couch. This is how we developed the internet to work for us.

Here, authentication comes in and every web resource wants to know who you are because your details are their asset as well as responsibility to keep it safe. This security is maintained by HTTP which is a set of rules that determines how data is exchanged between resources. HTTP authentication is a scenario of secure communication between users and online resources. Let’s understand what is HTTP authentication and other know-hows of its working to ensure security in the digital world.

What is HTTP Authentication?

HTTP Authentication is a security mechanism to verify the user who is eligible to access the web resource. It involves communication between client and server using HTTP header where server requests user’s credentials for authentication. The client in response provides the information in the header. Here’s the concept is based on web authentication through HTTP standards to ensure the security of users’ information. The more secured version is HTTPS, here S stands for Security Socket Layer (SSL) to establish encryption in communication. There are many schemes of HTTP authentication based on the security requirement and to make the credentials insufficient to crack the access for hackers.

Let’s drive you to some of the most used authentication schemes to enable access with security mode.

HTTP Authentication Schemes: The server determines various authentication schemes for the client to choose from. Schemes are the methods of authentication over the web. Present you the list of authentication schemes to make the concept clear.

Basic authentication: It is a challenge-response paradigm wherein the server requests credentials and in response client provides a username and password for authentication. It is a single factor authentication where the information is exchanged in clear text format.

Digest authentication: It is a more secure version of the basic authentication with the challenge-response procedure in addition to nonce value and MD5 algorithm to encrypt the data. Nonce value includes more information in credentials to level up the security.

Bearer authentication: Commonly known as token-based authentication with the multi-factor security mechanism. It adds an additional layer to the single-level security with the tokens to verify the credentials received from actual users. JWT (JSON Web Token) is a widely used medium for bearer.

NTLM: It’s an abbreviation of New Technology LAN Manager, a security protocol by windows to perform authentication of user’s identity without credentials and allow access to the resource.

Negotiate authentication: It is an updated version of NTLM that uses the Kerberos protocol as an authentication provider. Kerberos is faster and securer than NTLM.

The above schemes are used with a scale of security requirements of the web resource. The ‘Basic’ provides the lowest level of security while the other ones are used in the case of high-security requirements.

How does HTTP Authentication work?

HTTP has a general framework to control the access of the user to web resources. This framework depends on Authentication headers. Headers assist the users on how to provide their credentials and which scheme is used in the process. There are two types of headers WWW-Authenticate header and Proxy Authentication header.

The header syntax looks like this:

• WWW-Authenticate: <type> realm=<realm>
• Proxy-Authenticate: <type> realm=<realm>

Here, <type> specifies the scheme used in the authentication process. <realm> describes the scope of security to the client. Now, here’s a process of how HTTP authentication works with both the headers and maintains a paradigm in the process.

1. Request: The client makes a request to access the resource as an anonymous identity. The server doesn’t have any information about the client visiting the page.
2. Challenge: After detecting a visitor, the server responds to the client with 401 (Unauthorized) response status as a challenge to verify the identity and instructions on how to verify the in the header (eg: WWW-Authenticate).
3. Response: The client responds to the server’s challenge with the required credentials commonly, username, and password to authenticate the identity and access the resource.
4. Proxy Authentication: In case you use a proxy server to verify as an intended client, the proxy server challenge client with 407 (proxy) authentication status. Here, the proxy server gives authentication on behalf of the client to access the resource.
5. Verification: After receiving the credentials (also through proxy header) the server verifies them and if they are not valid, the server sends 403 (forbidden) response status. In case credentials prove to be valid, the client receives a welcome note.

These are some easy-to-grasp steps for HTTP authentication. The process is a whole lot more complicated in the back-end systems. With every possible way emerging to crack the access by hackers, security is added up with the layers on the existing mechanisms. Starting from Single-factor authentication, Two Factor Authentication, and how Multi-factor Authentication is widely a need of an hour. Banking and e-commerce services use strict multi-layer security mechanisms to ensure social security to data including payment details. Hence, HTTP protocol ensures safe communication between resources over the internet.