Encrypted Malicious Traffic Detection Based on Ensemble Learning -- A Federated Learning Assisted Conditional Privacy Preserving Scheme for Vehicle Networks -- Dissecting Membership Inference Risk in Machine Learning -- Webshell Detection Based on Explicit Duration Recurrent Network -- A Practical Botnet Traffic Detection System using GNN -- Vulnerability and Transaction behavior based detection of Malicious Smart Contracts -- A novel method of template protection and two-factor authentication protocol based on biometric and PUF -- Realizing Information Flow Control in ABAC Mining -- Weak Password Scanning System for Penetration Testing -- Environmental Adaptive Privacy Preserving Contact Tracing System for Respiratory Infectious Diseases -- A Privacy-Preserving Logistics Information System with Traceability -- Post-quantum Key Escrow for Supervised Secret Data Sharing on Consortium Blockchain -- Flexible and Survivable Single Sign-On -- The Analysis and Implication of Data Deduplication in Digital Forensics.

The LNCS 13172 constitute the proceedings of the 13th International Symposium on Cyberspace Safety and Security, CSS 2021, held online, in November 2021. The 9 full papers and 5 short papers presented in this book were carefully reviewed and selected from 35 submissions. The conference focuses on Cyberspace Safety and Security, such as authentication, access control, availability, integrity, privacy, confidentiality, dependability and sustainability issues of cyberspace.