This book consists of refereed selected papers from the International Conference on Security & Privacy – ICSP 2020. The book is focused on the state-of-the-art developments of network security, secure cryptographic protocols, post-quantum cryptography, quantum cryptography, block-chain and cryptocurrency, IoT security and privacy, cloud security, machine learning in cybersecurity, and other disciplines related to security and privacy. In this book, a wide variety of basic security primitives are discussed along with recent developments in some advanced topics like functional encryption, two-party/multi-party computation, bitcoin, cryptocurrency, and post-quantum security.