“I Helped Solve the Final Zodiac Killer Cipher” – with David Oranchak

Summary David Oranchak (X, LinkedIn) joins Andrew (X; LinkedIn) to discuss his work helping to solve the 340 Zodiac cipher. Dave is a software developer and avid puzzle solver.

What You’ll Learn Intelligence

The difference between codes and ciphers

The cryptological methods used by the Zodiac killer

The history of cryptography and its importance to intelligence

How Dave and his team cracked the 340 Cipher

Reflections

Persistence and dedication

Average citizens as avid participants

And much, much more …

Quotes of the Week “It felt like we had gotten a brand new letter from the Zodiac Killer. You know, the case had been dormant for so long … We started to see the message coming through, it was like he was back to life so to speak, he was talking to us again after so many years of not saying anything. So that was kind of eerie to kind of hear the voice of a serial killer.” – David Oranchak.

Resources SURFACE SKIM *SpyCasts*

My Father the Navajo Code-Talker with Laura Tohe (2023)

Venice’s Secret Service with Ioanna Iordanou (2023)

El Chapo, the Sinaloa Cartel & Intelligence with Trial Reporter Noah Hurowitz (2022)

CYBER AUGUST: “So, You Want to Be a Codebreaker?” with Elonka Dunin and Klaus Schmeh (2021)

*Beginner Resources*

A brief history of cryptography: Sending secret messages throughout time, J. Schneider, IBM (2024) [Short article]

What is the Difference Between a Code and a Cipher? Mysterious Writings (2018) [Short Article]

Infamous Killers: The Zodiac Killer, A&E, YouTube (2017) [5 min. video]

DEEPER DIVE Books

Zodiac: The Shocking True Story of the Hunt for the Nation's Most Elusive Serial Killer, R. Graysmith (Berkley, 2007)

The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography, S. Singh (Anchor, 2000)

The Codebreakers: The Comprehensive History of Secret Communication from Ancient Times to the Internet, D. Kahn (Scribner, 1996)

Primary Sources

The Zodiac Killer FBI Case File (1969)

San Francisco Zodiac Letter (1969)

San Francisco Suspect Sketches (1969)

Zodiac’s 408 Cipher (1969)

Zodiac’s 340 Cipher (1969)

The Beale Papers (1885)

The Dorabella Cipher (1897)

Voynich Manuscript (ca. 1401-1599)

*Wildcard Resource* If you’re an amateur codebreaker and you feel inspired by this episode, try your hand at cryptanalysis with this FBI-created dot code. Erin tried, but could not begin to crack it – She’ll stick to podcasting.

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