What is HTTP Digest Authentication?

HTTP Digest Authentication is a security mechanism used to authenticate clients to a web server without sending passwords in plaintext, making it more secure than the basic HTTP authentication method. In Digest Authentication, the client first requests access to a resource, and the server responds with a "challenge" containing a nonce (a unique number) and other information.

The client responds by hashing the user's credentials (username and password) along with the server's nonce using an MD5 hash function. This hashed value is then sent to the server for verification. The server compares this value with its own hash calculation; if they match, access is granted.

Digest Authentication protects against replay attacks and ensures that the actual password is never transmitted over the network. However, it is still considered less secure compared to more modern authentication methods like OAuth or JWT (JSON Web Tokens).