Java Expert - I have a Rest API and I need to implement Dighest Authentication with Java

I have a Rest API and I need to implement Dighest Authentication with Java. The project is made with Java 1.8 and gradle, it has Spring, but I need it to be the simplest because I am not an expert on the subject and I want to only copy and paste the classes in the project. I will receive a REQUEST with some parameters in the header, such as: Date: Wed, 02 Nov 2016 09:17:54 GMT X-TransferTo-Apikey: 00000000-0000-0000-0000-000000000000 X-TransferTo-Nonce: 1478078334 X-TransferTo-Hmac: g41AgixMSFMQj0TZgyXIK6 + odCVgy76fxfGpAtWwhE8 = And from my side what I understand is that I must create a signature to validate my hmac vs the received hmac. I already have my apiSecret or password. An example that I found very similar to the parameters that will be sent to me are: nonce = int ([login to view URL] ()) date = [login to view URL] (usegmt = True) message = bytes (apikey + str (nonce) + date) .encode ('utf-8') secret = bytes (apisecret) .encode ('utf-8') hmac = [login to view URL] ([login to view URL] (secret, message, digestmod = [login to view URL]) .digest ()) Either way I think I should validate the signatures (hmac) and the nonce to avoid recursive attacks. .. In general that is the project.