Step-by-Step Spring Boot HMAC Authentication Tutorial

Integrate HMAC Authentication into Your Spring Boot Application

HMAC authentication is an important security feature for any web application. It ensures that the user and server share a secret key, making it possible to authenticate and authorize access to resources without having to transmit the user credentials over the internet. A successful implementation of HMAC authentication can be easily achieved by integrating the right frameworks and technologies into your Spring Boot application.

Overview

HMAC (Hash-based Message Authentication Code) is a secure authentication protocol used for establishing trust between two parties. The client and server both compute a digest from the same message using a shared secret key. The digest computed by both sides can then be compared to ensure that the message hasn’t been tampered with or altered. This authentication mechanism helps protect data from being intercepted in transit and prevents unauthorized users from accessing restricted resources.

Prerequisites

• Spring Boot 2+
• Apache Commons Codec
• Jackson JSON Processor

Step 1: Setting up the Dependencies

The first step in setting up HMAC authentication in your Spring Boot application is to add the required dependencies to your pom.xml file. In addition to the regular Spring Boot dependencies, you’ll need to include Apache Commons Codec and Jackson JSON Processor.

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-codec</artifactId>
    <version>1.14</version>
</dependency>

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.11.2</version>
</dependency>

Step 2: Creating HMAC Security Filters

We now need to create security filters that will be used to verify the HMAC token sent by the user. To do this, we’ll use the HttpServletRequestWrapper class and override the getHeaders() method to return a custom implementation of Map<String, String[]> that includes the HMAC token in the headers.

Once the filter is in place, we can implement the authentication logic by computing the HMAC digest from the request body and matching it against the token provided in the headers. If the values match, the user is authenticated.

Step 3: Verifying the HMAC Signature

To verify the HMAC signature, we’ll use an Apache Commons Codec library. We’ll generate an HMAC using the SHA-256 algorithm and a secret key shared between the server and user. Then we’ll compare the generated HMAC with the one sent in the request header. If they match, the authentication will be successful.

Step 4: Testing the Authentication Flow

At this point, you should be able to test the authentication flow in your Spring Boot application. Make sure to include the HMAC token in the request header and the request body when sending the request to the server. If everything was setup correctly, the server should respond with a success message.

Conclusion

In this article, we discussed how to integrate HMAC authentication into a Spring Boot application. We saw how to setup the necessary dependencies and create filters and authentication logic to verify the HMAC token sent by the user. Finally, we tested the authentication flow in our Spring Boot application.