Electronic medical records are a very important asset that must be secured in such a way that only patients and authorized personal can access them. The HL7 (Health Level 7) is a set of standards to transfer clinical and administrative data among hospital information systems. One of the main concerns of interchanging medical information is related to security. A system that transfers medical information needs to be secured to avoid information disclosure. The increasing use of mobile devices arises different challenges in terms of information security. Access to clinical information from a mobile device requires security mechanisms that allow to guarantee confidentiality, integrity and availability. In this paper we built a system prototype in which electronic health records can be interchanged between a mobile device and a medical information system in a secure way. Results show that health records can be properly secured in a mobile scenario with good performance in terms of computational resources.