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Digest authentication

In the Digest authentication scheme, a hash function is applied to a username and password before sending them over the network.

Digest authentication flow

The digest authentication flow looks as follows:

  1. A client makes a request without the Authorization header to a specific resource in a server application.

  2. A server responds to a client with a 401 (Unauthorized) response status and uses a WWW-Authenticate response header to provide information that the digest authentication scheme is used to protect a route. A typical WWW-Authenticate header looks like this:

    WWW-Authenticate: Digest realm="Access to the '/' path", nonce="e4549c0548886bc2", algorithm="MD5"
  3. Usually, a client displays a login dialog where a user can enter credentials. Then, a client makes a request with the following Authorization header:

    Authorization: Digest username="jetbrains", realm="Access to the '/' path", nonce="e4549c0548886bc2", uri="/", algorithm=MD5, response="6299988bb4f05c0d8ad44295873858cf"

    The response value is generated in the following way:

    a. HA1 = MD5(username:realm:password)

    b. HA2 = MD5(method:digestURI)

    c. response = MD5(HA1:nonce:HA2)

  4. A server validates credentials sent by the client and responds with the requested content.

Configure digest authentication

To send user credentials in the Authorization header using the Digest scheme, you need to configure the digest authentication provider as follows:

  1. Call the digest function inside the install block.

  2. Provide the required credentials using DigestAuthCredentials and pass this object to the credentials function.

  3. Optionally, configure the realm using the realm property.

val client = HttpClient(CIO) { install(Auth) { digest { credentials { DigestAuthCredentials(username = "jetbrains", password = "foobar") } realm = "Access to the '/' path" } } }
Last modified: 26 December 2022