The cyber-security of several industrial plants has been compromised for last years by some worms and viruses, such as Stuxnet, which was able to take control of the Supervisory Control And Data Acquisition (SCADA) system of a nuclear plant in Iran. The research community and the international standardization committees raised their awareness about protecting information in Substation Automation Systems (SAS). IEC 61850-5 and IEC 62351-6 standards respectively describe communication models and the security mechanisms to be deployed in current substations, but they present some inconsistencies. On the one hand, this standard mandates that RSA cryptosystem must be used to provide source authenticity of GOOSE and SV messages. However, despite expensive processors with crypto accelerators were utilized, execution times would exceed the maximum transfer times stated in the standard for most time critical applications. On the other hand, the recommended synchronization solution is the Precision Time Protocol (PTP), as defined in IEEE 1588-2008, which introduced an optional security extension based on old keyed hash algorithms that has also been demonstrated to be suboptimal due to latency times and required resources. The aim of this paper is to explore current available security solutions and study their applicability to the substation environment. Furthermore, as part of the future security framework, a MACsec-based security approach that allows different communication services with diverse performance and security requirements to live together within the substation network is proposed.

Over the last few years, Software-Defined Networking (SDN) has emerged as one of the most disruptive and profitable novelties in networking. SDN was originally conceived to improve performance and reduce costs in Ethernet-based networks and it has been widely adopted in data center and campus networks. Similarly, thanks to the introduction of SDN concepts, access networks will benefit from the higher control, the lower maintenance costs and the better remote access to devices of SDN. However, its application to access networks is not straightforward and imposes great challenges to vendors and network operators, since current SDN technologies are not prepared to handle the provisioning of user equipment, specific port management or QoS requirements of common access networks. Most recent trends dealing with the SDN-ization of access networks advocate for the use of simple devices at the customer premises and the virtualization of the networking functionalities, requiring the provisioning of Layer 2 services in many cases. In such a scenario, this paper presents an architecture that brings SDN to common access networks using legacy equipment. In a nutshell, the architecture is based on the abstraction of the access network as a wide area OpenFlow switch where QoS-enabled pipes are dynamically created leveraging the high granularity of the OpenFlow protocol for packet classification. Furthermore, the OpenFlow protocol itself has been extended in order to support the advanced QoS requirements that are common to most access networks. The architecture has been implemented for DOCSIS access networks and it has been validated and evaluated using a real testbed deployed at our laboratory. The obtained results show that the architecture remains compliant with the ITU-T QoS recommendations and that the cost of introducing the elements required by the architecture in terms of service performance is negligible.

One of the key research issues in further strengthening the role of railways in the transportation system is to achieve the highest possible level of cyber security against significant threats to the signaling and telecom systems. The European Rail Traffic Management System (ERTMS) was designed in the 1990s with the security measures and strategies available at the time. However, ERTMS' underlying communication technology, GSM-R, needs replacing, and replacement strategies are already underway. Due to their direct effects on safety, ERTMS security mechanisms also need updating to face current security threats. This article provides a security analysis of ERTMS' safety layer, Euroradio, in terms of current security threats. After identifying its vulnerabilities, we present four main recommendations: a more robust cryptographic mechanism, a new key distribution scheme, a new key storage and system integrity module, and a set of countermeasures for avoiding radio jamming attacks.

Reliability is a key research issue to promote the role of rail in the transportation system. An important set of critical and vital railway services, such as Traction Power Supply and Supervision Systems, relay currently on modern Supervisory Control and Data Acquisition (SCADA) systems. At the same time, these large scale and networked SCADA systems are deployed over heterogeneous wide area networks. Current strategies to warrant reliability on these systems focus on costly equipment redundancy or retransmission techniques with associated delay penalization. In this paper, we propose a MultiPath strategy with redundant policy to increase reliability in railway SCADA over TCP/IP systems. We built a hybrid simulation tool with real Modbus over TCP/IP equipment and validate our approach comparing the obtained results with three alternative strategies (default TCP/IP, backup and default delivery policy).

IP-enabled sensors can be globally addressable by any Internet-connected entity, and therefore, their protection presents different challenges than that of traditional sensors, as they are subject to any potential attacker in the Internet. For this reason, specific security protocols must be developed to address the security requirements of IP-enabled sensors. An interesting approach to achieve this aim is the Ladon security protocol, which allows resource-deprived devices to efficiently implement end-to-end authentication, authorisation and key establishment mechanisms. However, in so limited environments such as sensor networks, not only efficient protocols must be defined, but they must also be optimally parameterised. This paper constitutes a step forward in this direction. First, a state transition model of the Ladon protocol is presented to analytically describe its behaviour. Then, this model is used to select the most effective parameterisation of the protocol in terms of message retransmissions and execution of cryptographic operations. The obtained results show that the selected parameterisation allows maximising the probability of a successful secure session establishment, while keeping the overhead introduced by the protocol low. Additionally, the performance comparison carried out shows that Ladon outperforms alternative approaches to achieve the same objective in terms of message transmission and reception operations.