Key agreement is a fundamental security functionality by which pairs of nodes agree on shared keys to be used for protecting their pairwise communications. In this work we study key-agreement schemes that are well-suited for the mobile network environment. Specifically, we describe schemes with the following characteristics:• Non-interactive: any two nodes can compute a unique shared secret key without interaction;• Identity-based: to compute the shared secret key, each node only needs its own secret key and the identity of its peer;• Hierarchical: the scheme is decentralized through a hierarchy where intermediate nodes in the hierarchy can derive the secret keys for each of its children without any limitations or prior knowledge on the number of such children or their identities;• Resilient: the scheme is fully resilient against compromise of any number of leaves in the hierarchy, and of a threshold number of nodes in each of the upper levels of the hierarchy.Several schemes in the literature have three of these four properties, but the schemes in this work are the first to possess all four. This makes them well-suited for environments such as MANETs and tactical networks which are very dynamic, have significant bandwidth and energy constraints, and where many nodes are vulnerable to compromise. We provide rigorous analysis of the proposed schemes and discuss implementations aspects. *

Two-terminal ferroelectric synaptic weights are fabricated on silicon. The active layers consist of a 2 nm thick WOx film and a 2.7 nm thick HfZrO4 (HZO) film grown by atomic layer deposition. The ultra-thin HZO layer is crystallized in the ferroelectric phase using a millisecond flash at a temperature of only 500°C, evidenced by X-Rays diffraction. The current density is increased by four orders of magnitude compared to weights based on a 5 nm thick HZO film. Potentiation and depression (analog resistive switching) is demonstrated using either pulses of constant duration (as short as 20 nanoseconds) and increasing amplitude, or pulses of constant amplitude (+/- 1V) and increasing duration. The cycle-to-cycle variation is below 1%. Temperature dependent electrical characterization is performed on a series of device cycled up to 108 times: they reveal that HZO possess semiconducting properties. The fatigue leads to a decrease, in the high resistive state only, of the conductivity and of the activation energy.

In both commercial and defense sectors a compelling need is emerging for rapid, yet secure, dissemination of information to the concerned actors. Traditional approaches to information sharing that rely on security labels (e.g., Multi-Level Security (MLS)) suffer from at least two major drawbacks. First, static security labels do not account for tactical information whose value decays over time. Second, MLS-like approaches have often ignored information transform semantics when deducing security labels (e.g., output security label = max over all input security labels). While MLS-like label deduction appears to be conservative, we argue that this approach can result in both underestimation and overestimation of security labels. We contend that overestimation may adversely throttle information flows, while underestimation incites information misuse and leakage.In this paper we present a novel calculus approach to securely share tactical information. We model security metadata as a vector half-space (as against a lattice in a MLS-like approach) that supports three operators: Γ, + and ·. The value operator Γ maps a metadata vector into a time sensitive scalar value. The operators + and · support arithmetic on the metadata vector space that are homomorphic with the semantics of information transforms. We show that it is unfortunately impossible to achieve strong homomorphism without incurring exponential metadata expansion. We use B-splines (a class of compact parametric curves) to develop concrete realizations of our metadata calculus that satisfy weak homomorphism without suffering from metadata expansion and quantify the tightness of values estimates in the proposed approach.

Recently, risk-based information trading has emerged as a new paradigm for securely sharing information across traditional organizational boundaries. In this paradigm, the risk of sharing information between organizations is characterized using expected losses (due, for example, to (un)intended information disclosure) and billed to a recipient. However, within risk-based information trading systems, quantifying the risks associated with sharing information is a non-trivial task, particularly when risk calculations depend on a number of factors. In this paper we introduce a data-centric metadata framework that extends risk-based information trading approaches by allowing one or more domains to exchange sensitive information based on metadata evaluated against internal risk assessments of the domains. We present a use case of our metadata framework using a coalition military scenario, wherein information flows can be controlled and regulated by our framework whilst allowing sufficiently high-quality tactical information to be disseminated 1 •

Abstract-In this paper we describe an algorithm for the distribution of trust authority functions such as key generation and distribution in tactical mobile ad hoc networks. Such networks cannot rely on existing infrastructures and must operate under severe resource constraints. Moreover, network partitioning and node failure, including Byzantine failures must be compensated in tactical networks. We propose the combination of metrics on both network state and beliefs or trust in other nodes to form a composite metric for use in a clustering algorithm. The effectiveness and other characteristics of this improved clustering algorithm are then evaluated and analyzed in a simulation environment, demonstrating a significant improvement over the baseline clustering algorithm.

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In this paper we present a new key-revocation scheme for ad hoc network environments with the following characteristics:• Distributed: Our scheme does not require a permanently available central authority.• Active: Our scheme incentivizes rational (selfish but honest) nodes to revoke malicious nodes.• Robust: Our scheme is resilient against large numbers of colluding malicious nodes (30% of the network for a detection error rate of 15%).• Detection error tolerant: Revocation decisions fundamentally rely on intrusion detection systems (IDS). Our scheme is active for any meaningful IDS (IDS error rate < 0.5) and robust for an IDS error rate of up to 29%.Several schemes in the literature have two of the above four characteristics (characteristic four is typically not explored). This work is the first to possess all four, making our revocation scheme well-suited for environments such as ad hoc networks, which are very dynamic, have significant bandwidthconstraints, and where many nodes must operate under the continual threat of compromise.

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