This book constitutes the refereed proceedings of the 13th International Conference on Security, Privacy, and Anonymity in Computation, Communication, and Storage, Spa CCS 2020, held in Nanjing, China, in December 2020. The 30 full papers were carefully reviewed and selected from 88 submissions. The papers cover many dimensions including security algorithms and architectures, privacy-aware policies, regulations and techniques, anonymous computation and communication, encompassing fundamental theoretical approaches, practical experimental projects, and commercial application systems for computation, communication and storage. Spa CCS 2020 is held jointly with the 11th International Workshop on Trust, Security and Privacy for Big Data (Trust Data 2020), the 10th International Symposium on Trust, Security and Privacy for Emerging Applications (TSP 2020), the 9th International Symposium on Security and Privacy on Internet of Things (SPIo T 2020), the 6th International Symposium on Sensor-Cloud Systems (SCS 2020), the 2nd International Workshop on Communication, Computing, Informatics and Security (CCIS 2020), the First International Workshop on Intelligence and Security in Next Generation Networks (ISNGN 2020), the First International Symposium on Emerging Information Security and Applications (EISA 2020).