This LNCS-volume set in constitutes the refereed proceedings of the 31st Australasian Conference on Information Security and Privacy, ACISP 2026, held in Perth, WA, Australia, during July 69, 2026.

The 69 full papers presented in this volume were carefully reviewed and selected from 260 submissions. The papers are organized in the following topical sections:

Part I: Applied Cryptography and Cryptanalysis; AI, Machine Learning, and Trustworthy AI Security; Network, System, and Software Security; Blockchain, Smart Contracts, and Decentralized Security; Privacy, Authentication, and Cyber-Physical Systems Security.

Part II: Applied Cryptography, Encryption, and Cryptanalysis; AI, Machine Learning, and Trustworthy AI Security; Privacy, Trust, and Secure Systems.

Part III: Applied Cryptography and Post-Quantum Security; AI, Machine Learning, and Adversarial Security; Privacy, and Secure Distributed Systems; System Security, Privacy, and Secure Computing.

Inhalt
.- Applied Cryptography and Cryptanalysis. .- Automated Tool for Finding Practical Collisions on SPN-based Hash Functions. .- Meet-LWE with Hints: Solving Ternary LWE with Information Leakage. .- Compact All-but- Vector Commitments for MPC-in-the-Head Signatures. .- Analyzing Forgery Security of LeMac: Tight Bounds and Impact of Padding. .- Efficient Zero Knowledge Proofs for Committed Symmetric Boolean Functions From VOLE-in-the-Head. .- Cryptanalytic Extraction of Convolutional Neural Networks. .- Towards Public Tracing: Collaborative Traceable Secret Sharing. .- Improved Tightly Secure (ID-based) Signatures in the AGM. .- Transparent Fully Batchable Polynomial Commitment with Application to Scalable VSS. .- AI, Machine Learning, and Trustworthy AI Security. .- Okara: Detection and Attribution of TLS Man-in-the-Middle Vulnerabilities in Android Apps with Foundation Models. .- Enhancing Backdoor Persistence under Uncontrolled Federated Clients: A Bidirectional Adversarial and Redundant Embedding Framework. .- Detection and Interpretation of Malicious Network Traffic via a novel 8-Channel Image Representation. .- Retention-Consistent Concept Unlearning for Diffusion Models. .- Network, System, and Software Security. .- ST-Mamba: Spatio-temporal Feature-Based Encrypted Traffic Analysis Using Mamba Network. .- RC-MDNet: Risk-Controlled Malicious Domain Detection for Open-World Network Security. .- CogSpy: Cognition-Driven PIN Inference against Layout-Randomized Soft Keyboards. .- Shielding MCP Tool: A Secure Execution Framework using TEE and Automated Trimming. .- Blockchain, Smart Contracts, and Decentralized Security. .- ServiceChain: A Verifiable Cloud Service Framework for Resource-Constrained Blockchain Nodes. .- Prompt to Pwn: Automated Exploit Generation for Smart Contracts. .- Secure Sealed-bidding Networks via Conditional Time-aware Access Authorization. .- The Dark Side of Upgrades: Uncovering Insecurity in Smart Contract Upgrades. .- Privacy, Authentication, and Cyber-Physical Systems Security. .- Missing the Link? Enhancing the Security of Digital Car Keys With Secure Session Linking and Hardware Trust. .- Information-Theoretic Privacy for Long-Term Share Storage on Noisy Media.