Digital signatures, nowadays, are a widely used mechanism. They are mainly used to sign digital documents and issue electronic invoices, among other things.

Among the benefits of using them are the following:

In order to electronically sign the information that we will exchange through RESTful web services, we will use the authentication mechanism known as DomainKeys Identified Mail (DKIM), which allows us to decorate messages with headers using the rules dictated by the DOSETA specification. This authentication mechanism is mainly used for e-mail identity verification; however, it also works over other protocols such as HTTP, and it is because of this fact we can integrate it with RESTful web services. Thus, we will inject metadata into our messages with the purpose of signing...