Programmable Bootstrapping Enables Efficient Homomorphic Inference of Deep Neural Networks -- Adversaries Strike Hard: Adversarial Attacks against Malware Classifiers using Dynamic API Calls as Features -- Privacy-Preserving Coupling of Vertically-Partitioned Databases and Subsequent Training with Gradient Descent -- Principal Component Analysis using CKKS Homomorphic Encryption Scheme -- DepthStAr: Deep Strange Arguments Detection -- Robust Multivariate Anomaly-Based Intrusion Detection System for Cyber-Physical Systems -- Privacy Preserving Password Strength Meters with FHE -- Automatic Detection of Water Stress in Corn Using Image Processing and Deep Learning -- Tortoise and Hares Consensus: the Meshcash Framework for Incentive-Compatible, Scalable Cryptocurrencies -- Game of Drones - Detecting Spying Drones Using Time Domain Analysis -- Privacy Vulnerability of NeNDS Collaborative Filtering -- Lawful Interception in WebRTC Peer-To-Peer Communication -- Hierarchical Ring Signatures Immune to Randomness Injection Attacks -- Theoretical aspects of a priori on-line assessment of data predictability in applied tasks -- Randomly Rotate Qubits, Compute and Reverse for Weak Measurements Resilient QKD and Securing Entanglement -- Warped Input Gaussian Processes for Time Series Forecasting -- History Binding Signature -- Effective enumeration of infinitely many programs that evade Formal Malware Analysis -- DNS-Morph: UDP-Based Bootstrapping Protocol For Tor -- Polynomial Time k-Shortest Multi-Criteria Prioritized and All-Criteria-Disjoint Paths -- Binding BIKE errors to a key pair -- Fast and Error-Free Negacyclic Integer Convolution using Extended Fourier Transform -- Efficient Secure Ridge Regression from Randomized Gaussian Elimination -- PolyDNN Polynomial Representation of NN for Communication-less SMPC Inference -- Use of Blockchain for ensuring Data Integrity in Cloud Databases -- The Coming AI Hackers -- Turning HATE Into LOVE: Compact Homomorphic Ad Hoc Threshold Encryption for ScalableMPC -- Fully Dynamic Password Protected Secret Sharing: simplifying PPSS operation and maintenance -- Early Detection of In-Memory Malicious Activity based on Run-time Environmental Features -- Software Integrity and Validation using Cryptographic Composability and Computer Vision -- Efficient Generic Arithmetic for KKW: Practical Linear MPC-in-the-Head NIZK on Commodity Hardware without Trusted Setup -- Trust and Verify: A Complexity-Based IoT Behavioral Enforcement Method -- Using a Neural Network to Detect Anomalies given an N-gram Profile -- Meta-X: A Technique for Reducing Communication in Geographically Distributed Computations -- Blindly Follow: SITS CRT and FHE for DCLSMPC of DUFSM -- Implementing GDPR in Social Networks using Trust and Context.

This book constitutes the refereed proceedings of the 5th International Symposium on Cyber Security Cryptography and Machine Learning, CSCML 2021, held in Be'er Sheva, Israel, in July 2021. The 22 full and 13 short papers presented together with a keynote paper in this volume were carefully reviewed and selected from 48 submissions. They deal with the theory, design, analysis, implementation, or application of cyber security, cryptography and machine learning systems and networks, and conceptually innovative topics in these research areas.