Internet of Things or IoT deployments are becoming more and more common. The list of use-cases for IoT is getting longer and longer, but some examples are smart home appliances and wireless sensor networks. When IoT devices are deployed and used over an extended time, it is not guaranteed that one owner will control the IoT devices over their entire lifetime. If the ownership of an IoT system shall be transferred between two entities, secure ownership transfer arises. In this paper we propose a protocol that enables secure ownership transfer of constrained IoT devices. The protocol is resource-efficient and only rely on symmetric cryptography for the IoT devices. The protocol has been rigorously analyzed to prove the state security requirements. The security analysis has been done partially using formal protocol verification tools, particularly Tamarin Prover. To show our proposed protocol’s resource efficiency, we have done a proof of concept implementation. This implementation, for constrained IoT devices, has been used to verify the efficiency of the protocol. 

DTLS is a transport layer security protocol designed to provide secure communication over unreliable datagram protocols. Before starting to communicate, a DTLS client and server perform a specific handshake in order to establish a secure session and agree on a common security context. However, the DTLS handshake is affected by two relevant issues. First, the DTLS server is vulnerable to a specific Denial of Service (DoS) attack aimed at forcing the establishment of several half open sessions. This may exhaust memory and network resources on the server, so making it less responsive or even unavailable to legitimate clients. Second, although it is one of the most efficient key provisioning approaches adopted in DTLS, the pre-shared key provisioning mode does not scale well with the number of clients, it may result in scalability issues on the server side, and it complicates key re-provisioning in dynamic scenarios. This paper presents a single and efficient security architecture which addresses both issues, by substantially limiting the impact of DoS, and reducing the number of keys stored on the server side to one unit only. Our approach does not break the existing standard and does not require any additional message exchange between DTLS client and server. Our experimental results show that our approach requires a shorter amount of time to complete a handshake execution, and consistently reduces the time a DTLS server is exposed to a DoS instance. We also show that it considerably improves a DTLS server in terms of service availability and robustness against DoS attack.

The infrastructure cloud (IaaS) service model offers improved resource flexibility and availability, where tenants – insulated from the minutiae of hardware maintenance – rent computing resources to deploy and operate complex systems. Large-scale services running on IaaS platforms demonstrate the viability of this model; nevertheless, many organisations operating on sensitive data avoid migrating operations to IaaS platforms due to security concerns. In this paper, we describe a framework for data and operation security in IaaS, consisting of protocols for a trusted launch of virtual machines and domain-based storage protection. We continue with an extensive theoretical analysis with proofs about protocol resistance against attacks in the defined threat model. The protocols allow trust to be established by remotely attesting host platform configuration prior to launching guest virtual machines and ensure confidentiality of data in remote storage, with encryption keys maintained outside of the IaaS domain. Presented experimental results demonstrate the validity and efficiency of the proposed protocols. The framework prototype was implemented on a test bed operating a public electronic health record system, showing that the proposed protocols can be integrated into existing cloud environments.

We point out the risks of protecting relational databases viaSearchable Symmetric Encryption (SSE) schemes by proposing an infer-ence attack exploiting the structural properties of relational databases.We show that record-injection attacks mounted on relational databaseshave worse consequences than their file-injection counterparts on un-structured databases. Moreover, we discuss some techniques to reducethe effectiveness of inference attacks exploiting the access pattern leak-age existing in SSE schemes. To the best of our knowledge, this is thefirst work that investigates the security of relational databases protectedby SSE schemes.

Software-Defined Networking (SDN) is a novel architectural model for cloud network infrastructure, improving resource utilization, scalability and administration. SDN deployments increasingly rely on virtual switches executing on commodity operating systems with large code bases, which are prime targets for adversaries attacking the network infrastructure. We describe and implement TruSDN, a framework for bootstrapping trust in SDN infrastructure using Intel Software Guard Extensions (SGX), allowing to securely deploy SDN components and protect communication between network endpoints. We introduce ephemeral flow-specific pre-shared keys and propose a novel defense against cuckoo attacks on SGX enclaves. TruSDN is secure under a powerful adversary model, with a minor performance overhead.

This paper presents the first results from the ongoing research project HASPOC, developing a high assurance virtualization platform for the ARMv8 CPU architecture. Formal verification at machine code level guarantees information isolation between different guest systems (e.g.~OSs) running on the platform. To use the platform in networking scenarios, we allow guest systems to securely communicate with each other via platform-provided communication channels and to take exclusive control of peripherals for communication with the outside world. The isolation is shown to be formally equivalent to that of guests executing on physically separate platforms with dedicated communication channels crossing the air-gap. Common Criteria (CC) assurance methodology is applied by preparing the CC documentation required for an EAL6 evaluation of products using the platform. Besides the hypervisor, a secure boot component is included and verified to ensure system integrity.

The fifth generation wireless system (5G) is expected to handle with an unpredictable number of heterogeneous connected devices while guaranteeing a high level of security. This paper advances a groupbased Authentication and Key Agreement (AKA) protocol that contributes to reduce latency and bandwidth consumption, and scales up to a very large number of devices. A central feature of the proposed protocol is that it provides a way to dynamically customize the trade-off between security and efficiency. The protocol is lightweight as it resorts on symmetric key encryption only, hence it supports low-end devices and can be already adopted in current standards with little effort. Using ProVerif, we prove that the protocol meets mutual authentication, key confidentiality, and device privacy also in presence of corrupted devices, a threat model not being addressed in the state-of-the-art group-based AKA proposals. We evaluate the protocol performances in terms of latency and bandwidth consumption, and obtain promising results.

We propose a simple and efficient searchable symmetric encryption scheme based on a Bitmap index that evaluates Boolean queries. Our scheme provides a practical solution in settings where communications and computations are very constrained as it offers a suitable trade-off between privacy and performance.

This paper addresses the problem of protecting distributed IoT units from network based attacks while still having a high level of availability. In particular we suggest a novel method where the IoT device execution state is modeled with a suitable high level application model and where the execution state of the application of the IoT device is 'mirrored' in a cloud executed machine. This machine has very high availability and high attack resistance. The IoT device will only communicate with the mirror machine in the cloud using a dedicated synchronization protocol. All essential IoT state information and state manipulations are communicated through this synchronization protocol while all end application communication directed towards the IoT units is done towards the mirror machine in the cloud. This gives a very robust and secure system with high availability at the price of slower responses. However, for many non-real time IoT application with high security demands this performance penalty can be justified.

The Datagram Transport Layer Security (DTLS) protocol is highly vulnerable to a form of denial-of-service attack (DoS), aimed at establishing a high number of invalid, half-open, secure sessions. Moreover, even when the efficient pre-shared key provisioning mode is considered, the key storage on the server side scales poorly with the number of clients. SICS Swedish ICT has designed a security architecture that efficiently addresses both issues without breaking the current standard.