Alastair MacGibbon has resigned from his role as the government\u2019s most senior cyber security advisor.\nMacGibbon has served as Deputy Secretary and National Cyber Security Advisor at the Department of Home Affairs, and the head of the Australian Cyber Security Centre (ACSC) since December 2017.\n \nHis resignation from the dual role was confirmed in an announcement by Australian Signals Directorate (ASD) Director-General Mike Burgess on Saturday.\n \nBurgess called him the \u201cface of cyber security in Australia\u201d who had \u201chelped raise the nation\u2019s cyber security standards\u201d.\n \n\u201cI\u2019d also like to recognise and thank Alastair for his tireless work in tackling the challenge of helping those we serve to better understand how to identify and manage the nation\u2019s cyber security risks more effectively,\u201d Burgess said in a statement.\n \nMacGibbon joined the public sector in 2015 as the government\u2019s inaugural eSafety Commissioner. In 2016 he was appointed by then Prime Minister Malcolm Turnbull to the role of Special Adviser to the Prime Minister on Cyber Security, within Department of the Prime Minister and Cabinet. He took up his current two roles at the end of 2017, remaining with the ACSC as it was absorbed into the ASD.\n \nDuring his time in the public service MacGibbon produced a report on the problems surrounding the online 2016 Census which found a range of shortcomings in the approach of ABS and IBM, concluding the DDoS attack was \u201cpredictable and defeatable\u201d.\n \nHe defended the government\u2019s controversial encryption legislation \u2013 theTelecommunications and Other Legislation Amendment (Assistance and Access) Bill 2018\u2013 which many in the private sector claimed will \u201cprofoundly undermine\u201d the reputation of Australian software and hardware manufacturers in international markets.\n \n\u201cSo no-one\u2019s talking about backdoors here,\u201d MacGibbon said of the \u2018aabill\u2019 in 2017.\n \nMore recently MacGibbon and his team analysed the compromise of the Australian parliament\u2019s computer network.\n \nBurgess said MacGibbon \u2013 a former agent with the Australian Federal Police \u2013 left a \u201cconsiderable legacy\u201d.\n \nMacGibbon will be returning to the private sector following his last day with the public service on May28.\n \n\u201cOne of the biggest challenges for Australia in cyber security sits with the private sector and in particular those who own and operate critical infrastructure. Indeed most of the cyber security heavy lifting is done by the private sector. Alastair\u2019s decision to return to the private sector means he is not lost to this important cause,\u201d Burgess said.\n \nLieutenant general John Frewen, Principal Deputy Director-General at the ASD, will lead the ACSC in an acting capacity until a permanent replacement can be found.