Electronic Product Code (EPC) refers to a numbering standard developed to uniquely identify physical objects, loads, locations, assets and other entities which are to be tracked or otherwise identified. The tracking technology consists of assigning Radio Frequency Identification (RFID) tags, holding universally unique EPC codes, to the entities to be identified. While the EPC-RFID technology is used to identify and capture data about the physical objects to be tracked in a supply chain, the EPCglobal Network ensures the exchange of the captured data between supply chain stakeholders. Such a real-time data exchange increases visibility and efficiency throughout the supply chain, and thus it increases both company profitability and customer satisfaction. The EPCglobal Network can be regarded as the backbone for the future Internet of Things (IoT). We focus our work in this thesis on Discovery Services (DS); a suite of network lookup services enabling users to retrieve all relevant information sources with regards to a given EPC. They can be viewed as search engines for the future business infrastructure deployed in the IoT. Motivated by the unprecedented and incessantly growing amount of EPC data, the expected epidemic growth in the solicitation frequency of the lookup service, and also the foreseen exceptionally large flow of highly sensitive EPC information, we focus on proposing solutions to problems pertaining to two main challenges; architecture design of Discovery Services and their security. On the architecture design level, we propose novel DS architectures with focus directed towards meeting four major requirements; network scalability, query responsiveness, service extensibility and acceptance. On the security level, we propose probabilistic security schemes aiming at securing even further Discovery Services in the IoT in general, and in the EPCglobal network in particular.