arXiv subjects

Stylianos Basagiannis

Publications and source records attributed to Stylianos Basagiannis.

10 recordsLinked to original sources

arXiv2026

Hierarchical Security Monitoring for Edge-IoT: A Formal Methods Approach

Cyber resiliency in edge-IoT deployments is fundamentally an economic problem: detection must keep critical processes operating under attack, but defender resources (compute, bandwidth, operator attention) are bounded. Centralised cloud monitoring offers expressive cross-device detection at prohibitive bandwidth cost; purely edge-local monitoring is cheap but blind to coordinated multi-device attacks where the asymmetric balance favours the attacker. We propose a lightweight hierarchical security-monitoring framework, built on formal runtime-verification methods, that occupies the practical middle ground at quantified cost. Each edge device runs a lightweight TeSSLa stream specification (size, payload validity, rate, and timestamp-drift predicates) that emits a four-valued verdict per aggregation window at sub-microsecond per-event cost; the gateway runs a parametric first-order MonPoly monitor over the per-device verdict streams at microsecond-scale per-verdict cost. The edge-to-gateway uplink carries roughly one Boolean per aggregation window per node, orders of magnitude smaller than the raw packet stream. The gateway tier detects coordinated attack patterns that no single-node monitor can see, shifting the asymmetric cost balance toward the defender. Every alert carries a witness set naming the device, the monitor tier, and the predicate that fired, providing an auditable record of the decision. We evaluate the framework on a container-host testbed spanning nominal and attacker nodes across four attack classes (buffer overflow, time spoofing, denial-of-service, and mixed advanced-persistent-threat patterns), and describe the edge- and gateway-tier specifications together with the cost-versus-coverage trade-off as monitor levels are added.

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arXiv2026

Hybrid Hierarchical Runtime Verification for Edge-IoT Security: Combining MonPoly and RTLola

Security monitoring of edge-IoT fleets faces three structural challenges. (i) A per-node monitor is cheap but cannot see attacks that coordinate across devices. (ii) A cloud monitor sees the full fleet but pays for that view in bandwidth. (iii) Even at the cloud, a monitor built on a single RV engine can be fooled by an attacker who compromises a device, raises one malicious request, and then goes silent: once the events stop, an event-triggered monitor has nothing left to evaluate. We propose a three-layer hierarchical runtime-verification framework that addresses all three. The edge layer classifies events as they happen, the gateway layer aggregates short windows of per-device behaviour, and the cloud layer runs two complementary RV engines. MonPoly handles first-order temporal correlation over the merged alert stream: coordinated overflow (which genuinely quantifies across devices) plus per-device multi-vector APT, escalation, and persistent-campaign patterns. RTLola handles a time-triggered silent-node property that an event-triggered engine cannot detect within a bounded delay under fleet silence. We evaluate the framework on a 15-actor Docker testbed covering eight attack profiles plus a silent-bypass scenario. In the controlled labelled testbed, every device-attributable incident the framework raises names an attacker-labelled device, and the RTLola tier catches silent-bypass attempts the event-triggered tier misses. Per-event monitoring stays in the microsecond range at the edge and gateway, with low end-to-end alert-to-incident latency at the cloud.

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arXiv2026

Formal Runtime Verification for Tool-Using LLM Agents: An Offline Same-Benchmark Study on AgentDojo and STAC

Guardrails for tool-using LLM agents are usually application-specific rules, which makes multi-step, data-dependent safety policies hard to specify, audit and reuse. As a declarative alternative, we evaluate metric first-order temporal logic (MFOTL), replaying the recorded trajectories that AgentDojo, STAC and R-Judge already ship through the unmodified MonPoly monitor, offline and without running an agent. On these corpora, five generic obligations flag 71.8% of STAC attack chains and 70.1% of successful AgentDojo attacks, but also fire on 29.3% of benign runs. This imprecision stems from the corpora rather than the logic: they rarely record approvals and never record timestamps, so history-dependent obligations reduce to detecting risky action types. Where the trace does carry relational context, provenance-aware policies discriminate better; that context, however, is itself attackable, and one planted line defeats a naive provenance check on 94-99% of the runs it would otherwise flag. Binding provenance to the lookup that produced it closes this evasion at no cost in detection or benign firing. Taken together, these results show that formal temporal monitoring adds value exactly when the trace exposes trustworthy history. We therefore quantify how far current benchmarks are from that point and propose a twelve-field enforcement-ready trace schema.

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arXiv2026

Explainable Rule Mining of IPv6 Extension-Header Presence Patterns from Paired-Vantage Captures

IPv6 extension headers (EHs), such as fragmentation, segment routing, and in-situ telemetry, are operationally important yetwidely dropped in transit, and characterising their behaviour from packet captures is a recurring measurement problem. We ask whetheran explainable miner can recover human-readable rules of EH behaviour, and we contribute two reusable tools: a negative-control protocol that diagnoses whether a mined "temporal" network rule reflects genuine cross-packet dynamics or mere within-packetco-occurrence, and a sender-conditioned, per-family EH-retention measurement. Applying an interpretable temporal-logic rule miner to the JAMES paired-vantage dataset, we recover a portable Fragment-EH rule that the protocol reveals to be a within-packet,near-definitional co-occurrence rather than a temporal pattern, so the temporal-logic machinery does no work for this dominant rule;the retention measurement independently recovers the expected within-window ordering of EH observability. Our main result istherefore an honest, controlled negative finding, corroborated by executed decision-tree and large-language-model baselines: on theevaluated JAMES traces network-temporal structure does not carry the dominant Fragment-EH signal, and we supply the controls thatestablish when it would, validated on a synthetic positive control containing a genuine cross-packet dependency.

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arXiv2026

Mission-Aware Attestation Envelopes for Time-Critical Autonomous Action: A Hardware-in-the-Loop V2I Study

An autonomous system that asks for a privileged physical action is usually gated on integrity evidence: a platform proves what it is running, and the request is granted or refused on that basis. Such a gate is normally treated as a predicate, yet the evidence behind it has an age, the decision that consumes it has a latency, and the physical system that waits for it has a deadline. We formulate mission-aware attestation as a runtime assurance contract that holds only when integrity is valid, the evidence is fresh enough, and the decision completes inside a budget derived from the current physical state. The contract yields four operational outcomes where a binary gate yields two, separating a refusal caused by tampering from one caused by stale evidence and from one caused by a late decision. We evaluate it on a hardware-in-the-loop vehicle-to-infrastructure platform: a driving simulator supplies the physical state and the authorisation deadline, while a microcontroller on-board unit and a TPM-backed roadside unit running Linux integrity measurement supply the assurance evidence. A security-blind model admits the whole operating space and a hardware-informed one three quarters of it, and every point it refuses fails the freshness margin rather than the response margin. Moving the attestation interval across the range the verifier permits costs about as much as a fivefold scaling of the latency distribution, and the interval is directly configurable, which makes it the immediately actionable deployment parameter. If the freshness bound does not exceed the authorisation budget, every late decision is also stale and lateness becomes unobservable, so the attestation interval and the freshness bound cannot be chosen from security requirements alone.

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arXiv2026

Multi-Aspect Runtime Verification for Simulation-Based V&V of LLM-Enabled Autonomous Agents

LLM-based agents are entering decision-support roles in defence staff work, where the obligations they must respect are already written down and binding, and where retraining is not available as a control because models arrive as procured components. What can be placed under engineering control is the interface between the agent and the systems it acts on. Those obligations are at once spatial, temporal and text-semantic, and a violation typically lives in the composition of a multi-step interaction, which is why per-event guardrails miss sequential tool-attack chains. We present a multi-aspect runtime-verification framework that decomposes a natural-language policy clause into a typed spatial/temporal/semantic triple over one canonical event stream, checks each aspect with its own monitoring specification, and fuses the verdicts through a four-valued algebra that carries provenance. The spatial aspect is interpreted over a weighted two-sorted location graph in which mission geometry and information-release topology are one object; we show that these spatial obligations are not in general subsumed by a first-order temporal specification. The past-time aspect runs on the unmodified MonPoly engine, which agrees with our reference monitor at every time point. Across two mission domains, casualty evacuation and contested sustainment, and one civil domain, composition under the precautionary blocking policy drives attack success to zero with no observed false positives and microsecond-scale per-event cost, while every single aspect and every pair leaves a substantial share of attacks succeeding. In a closed-loop experiment a policy-naive planner reaches a violating state in most unshielded missions and in none when shielded, and four refused episodes in five still recover to a compliant outcome.

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arXiv2026

A Resilient Runtime-Verification Fabric for Security Monitoring of Critical Edge-IoT Infrastructure

Protecting critical infrastructure increasingly depends on continuously verifying large IoT fleets against formal security specifications at runtime. Yet the runtime-verification (RV) pipelines proposed for this task are typically single-host prototypes whose monitors read a shared log file, with no resilience to the failures such deployments incur: a crash or overload silently drops events, clock skew corrupts the ordering metric monitors require, a time-triggered "node has gone silent" property cannot fire when the network itself falls silent, and one slow consumer stalls the pipeline. Each failure is silent: the monitor keeps emitting verdicts over a corrupted view. We present RV-Fabric, a resilient delivery layer that carries the hierarchy over two brokers (MQTT for device ingest, a durable stream broker for backend delivery) and re-establishes five continuity guarantees: durable delivery under crashes, a trusted event order, progress under total silence, consumer isolation and flow control under bounded overload, each an invariant conditioned on broker durability. Above the transport, RV-Fabric makes evidence completeness part of runtime-verification semantics: every verdict carries a status (sound, degraded, incomplete or unavailable) derived from delivery gaps, retention pressure and liveness, so an incomplete stream cannot yield an unqualified all-clear. Under controlled fault injection on a containerised testbed, measured against a fault-free oracle using the real MonPoly engine, the shared-log baseline misses six of seven injected incidents, reporting each as an unqualified all-clear, whereas RV-Fabric preserves all seven; removing a delivery mechanism reintroduces silent loss, removing isolation costs only timeliness. Two published critical-infrastructure datasets, water-SCADA and IoT/IIoT, replay end-to-end.

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arXiv2011

Quantitative Analysis for Authentication of Low-cost RFID Tags

Formal analysis techniques are widely used today in order to verify and analyze communication protocols. In this work, we launch a quantitative verification analysis for the low- cost Radio Frequency Identification (RFID) protocol proposed by Song and Mitchell. The analysis exploits a Discrete-Time Markov Chain (DTMC) using the well-known PRISM model checker. We have managed to represent up to 100 RFID tags communicating with a reader and quantify each RFID session according to the protocol's computation and transmission cost requirements. As a consequence, not only does the proposed analysis provide quantitative verification results, but also it constitutes a methodology for RFID designers who want to validate their products under specific cost requirements.

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arXiv2009

Attacking an OT-Based Blind Signature Scheme

In this paper, we describe an attack against one of the Oblivious-Transfer-based blind signatures scheme, proposed in [1]. An attacker with a primitive capability of producing specific-range random numbers, while exhibiting a partial MITM behavior, is able to corrupt the communication between the protocol participants. The attack is quite efficient as it leads to a protocol communication corruption and has a sound-minimal computational cost. We propose a solution to fix the security flaw.

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arXiv2009

State Space Reduction with Message Inspection in Security Protocol Model Checking

Model checking is a widespread automatic formal analysis that has been successful in discovering flaws in security protocols. However existing possibilities for state space explosion still hinder analyses of complex protocols and protocol configurations. Message Inspection, is a technique that delimits the branching of the state space due to the intruder model without excluding possible attacks. In a preliminary simulation, the intruder model tags the eavesdropped messages with specific metadata that enable validation of feasibility of possible attack actions. The Message Inspection algorithm then decides based on these metadata, which attacks will certainly fail according to known security principles. Thus, it is a priori known that i.e. an encryption scheme attack cannot succeed if the intruder does not posses the right key in his knowledge. The simulation terminates with a report of the attack actions that can be safely removed, resulting in a model with a reduced state space.

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