In this thesis we discuss two demanding problems from the field of computer and communication security that involve …, other than in traditional computer security problems, the adversary has a lot of control over the situation. The untrusted … ways: We propose relaxed, but still practically useful, notions of security for the DSP problem; we identify theoretical …

an untrusted service provider. We explore the limits of the security that is achievable in these scenarios. When … discussing security, we refer to the state of the art definitions from cryptography and complexity theory. The key contributions … prove its correctness and security. - We describe a new searchable encryption scheme that exceeds existing analogues with …

information about this object. This thesis discusses the information security challenges involved in the design and use of an IOT … discussed, including multilateral security and the client perspective, which have been neglected in IOT standards and research … literature so far. Second, we conduct a detailed security analysis of the most influential standard Object Naming Service (ONS …