Abstract
Nowadays, Virtual Reality (VR) and Augmented Reality (AR) systems are not exclusively associated with the gaming industry. Their potential is also useful for other business areas such as healthcare, automotive, and educational domains. Companies need to accompany technological advances and enhance their business processes and thus, the adoption of VR or AR technologies could be advantageous in reducing resource usage or improving the overall efficiency of processes. However, before implementing these technologies, companies must be aware of potential cyberattacks and security risks to which these systems are subject. This study presents a survey of attacks related to VR and AR scenarios and their risk assessment when considering healthcare, automation, education, and gaming industries. The main goal is to make companies aware of the possible cyberattacks that can affect the devices and their impact on their business domain. © 2023 IEEE.

Abstract
Traditional identity management (IdM) systems rely on third-party identity providers (IdPs) and are centralised, which can make them vulnerable to data breaches and other security risks. Self-sovereign identity (SSI) is a newer IdM model that allows users to control their own identities by using decentralised technologies like blockchain to store and verify them. However, SSI systems have their own security concerns, such as digital wallet vulnerabilities, blockchain threats and conflicts with general data protection regulation (GDPR). Additionally, the lack of incentives for issuers, verifiers and data owners could limit its acceptance. This paper proposes SPIDVerify, which is a decentralised identity verification framework that utilises an SSI-based architecture to address these issues. The framework uses a mixed method for acquiring a W3C standard verified credentials and to ensure that only a thoroughly verified entity acquires verified credential, and employs secure key cryptographic protocols; Diffie-Hellman (DH) and Extended Triple Diffie-Hellman (X3DH) for forward secrecy secure communication, single-use challenge-response for authentication, and Swarm network for decentralised storage of data. These methods enhance the security of the proposed framework with better resilience against impersonation and credential stealing. To evaluate the proposal, we have outlined the limitations in related works and demonstrated two scenarios to showcase the strength and effectiveness of SPIDVerify in dealing with the threats identified. We have also tested the methods used in SPIDVerify by measuring the time taken to execute certain processes. © 2023 IEEE.

Abstract
This paper further develops an architecture and design elements for a resource management and a signalling system to support the construction and maintenance of a mid-long term hybrid multicast tree for multimedia distribution services in a QoS guaranteed way, over multiple IP domains. The system called E-cast is composed of an overlay part - in inter-domain and possible IP level multicast in intra-domain. Each E-cast tree is associated with a given QoS class and is composed of unicast pipes established through Service Level Specification negotiations between the domain managers. The paper continues a previous work, by proposing an inter-domain signalling system to support the multicast management and control operations and then defining the resource management for tree construction and adjustment procedures in order to assure the required static and dynamic properties of the tree.

Abstract
This chapter proposes a novel concept towards the deployment of a networked 'Media Ecosystem'. The proposed solution is based on a flexible cooperation between providers, operators, and end-users, finally enabling every user first to access the offered multimedia services in various contexts, and second to share and deliver his own audiovisual content dynamically, seamlessly, and transparently to other users. Towards this goal, the proposed concept provides content-awareness to the network environment, network- and user context-awareness to the service environment, and adapted services/content to the end user for his best service experience possible, taking the role of a consumer and/or producer. © 2011 Springer-Verlag Berlin Heidelberg.

Abstract
With the ongoing increase of the network technologies' diversity and the integration of the user level applications, the legacy-style content-independent configuration of the security mechanisms cannot yields in efficient security solutions farther. Our work aims to contribute on the design of auto-reconfigurable (adaptive) security services that are capable to satisfy the application's security level required with minimal network resources' usage. In this paper we propose a new networkcentric security architecture design that relies on the current network security conditions and content-aware mechanisms. The architecture main functional blocks and the corresponding relationships are defined. This architecture shall supply three inter-domain composite user security services, named "public traffic", "secret content" and "private communication", as well as, attack source traceback and distributed access control functionalities.

Abstract
Factors such as the growing number of multimedia terminals, the constant increase of bandwidth available per user, and the large number of existing data sharing applications, are compelling users to generate and distribute their own content to restricted groups of other users. Inorder to support such scenario, we present an IMS-based solution that enables content distribution, in multicast, to groups of users, where the source of the content is also an end-user The proposed solution allows the source of content to configure the service, indicating a list of authorized receivers and both the transmission date and duration. Moreover, the proposed solution also allows the operator to manage the registered user profiles, to impose access control and to validate the configurations submitted by the users.