This Special Issue on cryptography and information security presents a diverse range of contributions, offering valuable insights into various facets of the field. The topics covered include surveying physical unclonable functions for authentication, communication protocols, challenges, and applications of Internet of Things security. Additionally, this issue discusses the development of a symmetric encryption solution derived from a binary-tree-fed mixed-network protocol, a novel deduplication method for cloud preservation with real-time ownership organization and optimization, and a low-intervention security model aimed at alleviating enterprise burdens through API utilization. Other contributions explore architectures designed to prevent low-rate denial-of-service attacks within drone environments, propose IoT-enabled lightweight authentication frameworks, and investigate the effects of long-range dependence on temporal resolution recovery in HEVC compressed-content environments. Furthermore, this issue introduces a novel framework utilizing API-based obfuscation techniques and discusses the secure application of medical IoT systems, lightweight cipher mechanisms for electronic commerce transactions, and a systematic review of information security in chatbots. Together, these contributions offer valuable insights into cryptography and information security, spanning from encryption solutions to IoT-enabled authentication architectures and beyond.