| 1963 - 1964 | Computer Programmer at ICL Computers Pty. Ltd. |
| 1965 - 1966 | Teacher in Mathematics and Science at Loreto College Kirribilli and North Ryde High School, New South Wales |
| 1966 | Bachelor of Science (BSc) completed at the University of New South Wales |
| 1967 - 1968 | Senior Tutor at the University of Melbourne |
| 1968 - 1970 | Senior Tutor at La Trobe University, Victoria |
| 1969 | Master of Science (MSc) completed at La Trobe University |
| 1970 | Lecturer at the Canberra College of Advanced Education (6 months) |
| 1970 - 1973 | Lecturer at the University of Newcastle, New South Wales |
| 1971 | Doctor of Philosophy (PhD) completed at La Trobe University |
| 1972 | Postdoctoral Fellow at the Department of Statistics of University of Waterloo, Canada (5 months) |
| 1973 | Visiting Associate Professor at Queen's University in Canada (4 months) |
| 1973 | Visiting Fellow in the Department of Computer Science at the University of Manitoba in Canada (5 months) |
| 1974 | Visiting Associate Professor at the State University of New York in Buffalo, USA (5 months) |
| 1974 - 1976 | Research Fellow / Senior Research Fellow at the Institute of Advanced Studies at Australian National University |
| 1976 - 1984 | Lecturer/Senior Lecturer/Reader in Applied Mathematics at the University of Sydney |
| 1979 - 1984 | Various Visiting Associate positions for 1 to 4 month stints at University of Manitoba (Canada), Concordia University (Canada), University of Indore (India), Mehta Research Institute (India) |
| 1984 - 1987 | Reader in Computer Science at the University of Sydney |
| 1986 - 1987 | Director of Postgraduate Studies in the Department of Computer Science at the University of Sydney |
| 1987 - 1988 | Visiting Professor in Computer Science at the University of Sydney |
| 1987 - 1989 | Professor and Head of Computer Science at University College at the Australian Defence Force Academy (ADFA) |
| 1987 - 1991 | Director of the Centre for Computer Security Research at the ADFA |
| 1989 | Various Visiting Professor/Associate positions for 1 to 3 month stints at the Institute for Comparative Studies of Culture (Japan); The University of Victoria (Canada); Royal Holloway and Bedford New College (London) |
| 1989 - 1991 | Honorary Associate in Computer Science at the University of Sydney |
| 1989 - 1991 | Professor of Computer Science at University College at ADFA |
| 1989 - 1991 | Director of the Centre for Communications Security Research at the ADFA |
| 1991 - 1992 | Professor of Computer Science and Engineering and Professor of Electrical Engineering and Director of the Center for Communication and Information Science at the University of Nebraska, USA |
| 1992 - | Director of the Centre for Computer Security Research at the University of Wollongong |
| 1992 - | Professor of Computer Science at the University of Wollongong, New South Wales |
| 1992 | Adjunct Professor of Electrical Engineering at the University of Nebraska, USA |
| 1994 - 1996 | Head of the Department of Computer Science at the University of Wollongong |
| 2000 - 2001 | Member of the National Electronic Authentication Council |
