This book constitutes the refereed post-conference proceedings of the Second International Conference on Applied Cryptography in Computer and Communications, AC3 2022, held May 14-15, 2022 and due to COVID-19 pandemic virtually. The 12 revised full papers and 2 short papers were carefully reviewed and selected from 38 submissions. They were organized in topical sections as follows: quantum-safe cryptographic solution; applied cryptography for IoT; authentication protocol; real-world applied cryptography; network attack and defense; security application.