Power languages and density

AbstractThe class of all languages can be seen as a distributive lattice with respect to a preorder defined by letter-to-letter morphisms. Maximal dense intervals in the lattice are investigated. The results are based on a construction that builds a new language, so-called power language, from subsets of a given language. Applications to grammar form theory and graph theory are also presented

Privacy Enhanced Fast Mutual Authentication in 5G Network Using Identity Based Encryption

Subscription privacy of a user has been a historical concern with all the previous generation mobile networks, namely, GSM, UMTS, and LTE. While a little improvement have been achieved in securing the privacy of the long-term identity of a subscriber, the so called IMSI catchers are still in existence even in the LTE and advanced LTE networks. Proposals have been published to tackle this problem in 5G based on pseudonyms, and different public-key technologies. This paper looks into the problem of concealing long-term identity of a subscriber and presents a protocol based on identity based encryption (IBE) to tackle it. The proposed solution can be extended to a mutual authentication and key agreement protocol between a serving network (SN) and a user equipment (UE). We name the protocol PEFMA (privacy enhanced fast mutual authentication). The SN does not need to connect with the home network (HN) on every PEFMA run. In PEFMA, both the user equipment (UE) and the SN has public keys. A UE sends the IMSI after encrypting it using the SN’s public key. Since both the UE and SN have public keys, PEFMA can run without contacting the HN. A qualitative comparison of different techniques show that our solution is competitive for securing the long-term identity privacy of a user in the 5G network.Peer reviewe

Multi-party Private Set Operations with an External Decider

A Private Set Operation (PSO) protocol involves at least two parties with their private input sets. The goal of the protocol is to learn the output of a set operation, e.g., set intersection, on the parties' input sets, without revealing any information about the items that are not in the output set. Commonly, the outcome of the set operation is revealed to parties and no one else. However, in many application areas of PSO, the result of the set operation should be learned by an external participant who does not have an input set. We call this participant the decider. In this paper, we present new variants of multi-party PSO, for the external decider setting. All parties except the decider have a private set. Parties other than the decider neither learn this result, nor anything else from this protocol. Moreover, we studied generic solutions to the problem of PSO in the presence of an external decider.Peer reviewe

Privacy-Aware Access Protocols for MEC Applications in 5G

Multi-access edge computing (MEC) is one of the emerging key technologies in fifth generation (5G) mobile networks, providing reduced end-to-end latency for applications and reduced load in the transport network. This paper proposes mechanisms to enhance user privacy in MEC within 5G. We consider a basic MEC usage scenario, where the user accesses an application hosted in the MEC platform via the radio access network of the mobile network operator (MNO). First, we create a system model based on this scenario. Second, we define the adversary model and give the list of privacy requirements for this system model. We also analyze the impact on user privacy when some of the parties in our model share information that is not strictly needed for providing the service. Third, we introduce a privacy-aware access protocol for the system model and analyze this protocol against the privacy requirements

Privacy-Preserving Access for Multi-Access Edge Computing (MEC) Applications

Multi-Access Edge Computing (MEC) is one of the emerging key technologies in Fifth Generation (5G) Mobile Networks, providing reduced end-to-end latency for applications and reduced load in the transport network. This paper is about user privacy in MEC within 5G. We consider a basic MEC usage scenario, where the user accesses an application hosted in the MEC platform via the radio access network of the Mobile Network Operator (MNO). First, we create a system model based on this scenario, then define the adversary model and privacy requirements for this system model. Second, we introduce a privacy-preserving access solution for the system model and analyze the solution against the privacy requirements.Peer reviewe

Distributed Usage Control

AbstractWith more and more personal data being collected and stored by service providers, there is an increasing need to ensure that their usage is compliant with privacy regulations and user preferences. We consider the specific scenario where promised usage is specified as metric temporal logic policies, and these policies can be verified against the database usage logs. Given the vast amount of data being collected, scalability is very important. In this work, we show how such usage monitoring can be performed in a distributed fashion for an expressive set of policies. Experimental results are given for a real-life use case to show the genericness and scalability of the results

AKMA Support in Multi SIM User Equipment

Multi SIM User Equipment (UE) can have more than one physical slot for Universal Integrated Circuit Card (UICC). The eUICC is an embedded version of the UICC, which cannot be physically removed from the communication device. Currently, 3rd Generation Partnership Project (3GPP) is working on developing Authentication and Key Management for Applications (AKMA), with which user can bootstrap authentication towards application server from his mobile subscription. We consider the scenario that may become common in devices with Multi SIM and eUICC, in which one subscription is used for primary services such as voice and data, and another subscription is used for AKMA services. In this scenario, the purpose is to use AKMA services simultaneously and without interrupting primary services. There are existing requirements for Multi SIM and eUICC, which restrain this scenario from being successful. The solution that we propose includes arrangements and adaptations, in order to provide secure and uninterrupted services of both primary and AKMA services.Peer reviewe

Privacy-friendly Discovery of Common Friends in P2P Networks

Peer reviewe