What is Basic Authentication?

ICSM Computer 777 27 Jul 2025

1 Answers

ICSM Computer 27 Jul 2025

Basic Authentication is a lightweight authentication scheme based on a username and password to gain access to a resource. It's an HTTP standard and functions by including credentials encoded in base64 with every request.

How Basic Authentication Works

A request is sent by the client that includes an Authorization header that appears as follows:

Authorization: Basic base64(username:password)

The server receives and decodes the credentials and checks them.
If legitimate, the server grants access; else, it sends 401 Unauthorized.

Example: Base64 Header

For username: admin, password: 1234
Base64 encoding of admin:1234 is:

Authorization: Basic YWRtaW46MTIzNA==

In Code

Example in C#

var client = new HttpClient();
var byteArray = Encoding.ASCII.GetBytes("admin:1234");
client.DefaultRequestHeaders.Authorization =
    new AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));

var response = await client.GetAsync("https://api.example.com/data");

Example in JavaScript (Fetch)

const headers = new Headers();
headers.set("Authorization", "Basic " + btoa("admin:1234"));

fetch("https://api.example.com/data", {
  method: "GET",
  headers: headers
});

Security Note

Base64 is not encryption, just encoding.
Use HTTPS always to protect credentials.
For better security, consider using token-based authentication (like OAuth or JWT) instead.

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