We address security solutions to protect the communication of the wireless components of a home health care system. We analyze especially the problem of exchanging secrets to satisfy authentication of entities. We outline some important aspects that must be guaranteed given the existence of low-cost and resource-constrained RFID components. Appropriate solutions must, therefore, enable several nodes, with different computing and communicating capabilities, to securely interact and communicate. Key words: Network Security; Wireless Security; RFID; Sensor Networks; Cryptographic Protocols.