SpyCast 5.14.24
Ep 633 | 5.14.24

“Codebreaking and Codemaking Down Under” – with John Blaxland and Clare Birgin

Show Notes


John Blaxland (XLinkedIn) and Clare Birgin (Wikipedia, LinkedIn) join Andrew (XLinkedIn) to discuss Australian codebreaking. John and Clare are coauthors of the new book Revealing Secrets

What You’ll Learn


  • The importance of SIGINT
  • Codebreaking in Australian intelligence
  • Australia’s role in WWII and the Cold War
  • The advent and evolution of cyber 


  • Strategic defense and offense 
  • The power, and danger, of communication

And much, much more …

Episode Notes

This week on SpyCast, Andrew was joined by John Blaxland and Clare Birgin, co-authors of the new book Revealing Secrets: An unofficial history of Australian Signals Intelligence and the advent of cyber. John is a professor of International Security & Intelligence Studies at the Australian National University, and was an instrumental collaborator on the creation of the three-volume Official History of ASIO. Clare, an ANU alumni, is a former Australian diplomat who served as Ambassador in Serbia, Hungary, and Romania, among others. 

The trio discuss the history of SIGINT in Australia: From World War II through the Cold War, signals intelligence remained a critical yet often overlooked element of Australian state strategy. In this episode, you’ll learn about particularly clever Australian codebreakers and the international relationships that have shaped Australia’s position in the world today. Tune in to learn more! 


The Australian National University’s motto is “Naturam primum cognoscere rerum,” or “First, to know the nature of things.” This phrase is thought to originate from the first-century BC poem “De rerum natura,” or “On the Nature of Things” by Roman philosopher Lucretius. This poem introduced atomic theory to the Roman audience – the ancient speculation that the world was made up of indivisible particles called atoms. 

Quotes of the Week

"What I've noticed with the Australians, and I think it's similar in the other the other Five Eyes countries, these people tend to be quite patriotic to do [Signals Intelligence]. They want to, they love their country, and it also seems to preserve very good qualities.” - Clare Birgin.



*Spotlight Resource* 

  • Revealing Secrets: An unofficial history of Australian Signals intelligence and the advent of cyber, Clare Birgin and John Blaxland (University of New South Wales Press, 2023) 


*Beginner Resources*



  • Spies & Sparrows: ASIO & the Cold War, P. Deery (Melbourne University Press, 2022)
  • Australia's First Spies: The Remarkable Story of Australia's Intelligence Operations, 1901-45, J. Fahey (Allen & Unwin, 2019)
  • The Secret Code-Breakers of Central Bureau: how Australia’s signals-intelligence network helped win the Pacific War, D. Dufty (Scribe US, 2018)
  • A man of intelligence: The life of Captain Eric Nave, Australian codebreaker extraordinary, I. Pfennigwerth (Rosenberg Publishing, 2006)



Primary Sources 

*Wildcard Resource*

  • Here’s a challenge – For their 75th Anniversary in 2022, the Australian Signals Directorate released a limited edition coin with multiple layers of code to crack on both sides. 
  • Think you can solve it? Check out the link above and test your code-cracking skills.