This book constitutes the refereed proceedings of the 28th Australasian Conference on Information Security and Privacy, ACISP 2023, held in Brisbane, QLD, Australia, during July 5-7, 2023.

The 27 full papers presented were carefully revised and selected from 87 submissions. The papers present and discuss different aspects of symmetric-key cryptography, public-key cryptography, post-quantum cryptography, cryptographic protocols, and system security.

This Festschrift is a celebration of Ed Dawson''s life and impact on research, teaching and leadership. Ed originally trained as a mathematician and first worked as a schoolteacher before joining Queensland Institute (later University) of Technology where he engaged with the emerging world of applied cryptology. He first concentrated on symmetric-key cryptography, analyzing randomness, searching for new building blocks and designing cryptographic engines, he later expanded his interests to public-key cryptography with a particular focus on the implementation aspects of elliptic curves.

Ed was made a Fellow of the IACR for his visionary service and for fostering the Asia-Pacific cryptographic community. He cofounded conferences, workshops, courses and communities, first in Australia and then throughout the Pacific Rim. Ed''s instincts and experiences were always interdisciplinary and he developed successful networks of researchers and practitioners in mathematics, computer science, engineering, business and law. In recent years he broadened his expertise to incorporate the human, socio-technical, aspects of security.

Throughout his career Ed was a noted teacher, mentor and motivator, building and encouraging teams with effort, knowledge, enthusiasm and humor. His successes are reflected in the papers contributed to this volume.

This book constitutes the refereed proceedings of the 28th Australasian Conference on Information Security and Privacy, ACISP 2023, held in Brisbane, QLD, Australia, during July 5-7, 2023.

The 27 full papers presented were carefully revised and selected from 87 submissions. The papers present and discuss different aspects of symmetric-key cryptography, public-key cryptography, post-quantum cryptography, cryptographic protocols, and system security.

This Festschrift is a celebration of Ed Dawson''s life and impact on research, teaching and leadership. Ed originally trained as a mathematician and first worked as a schoolteacher before joining Queensland Institute (later University) of Technology where he engaged with the emerging world of applied cryptology. He first concentrated on symmetric-key cryptography, analyzing randomness, searching for new building blocks and designing cryptographic engines, he later expanded his interests to public-key cryptography with a particular focus on the implementation aspects of elliptic curves.

Ed was made a Fellow of the IACR for his visionary service and for fostering the Asia-Pacific cryptographic community. He cofounded conferences, workshops, courses and communities, first in Australia and then throughout the Pacific Rim. Ed''s instincts and experiences were always interdisciplinary and he developed successful networks of researchers and practitioners in mathematics, computer science, engineering, business and law. In recent years he broadened his expertise to incorporate the human, socio-technical, aspects of security.

Throughout his career Ed was a noted teacher, mentor and motivator, building and encouraging teams with effort, knowledge, enthusiasm and humor. His successes are reflected in the papers contributed to this volume.