Cracking the Enigma Code (Encore)

Summary

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Everything Everywhere Daily: "Cracking the Enigma Code (Encore)"

Host: Gary Arndt
Date: November 9, 2025

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Episode Overview

In this encore episode, host Gary Arndt delves into one of World War II's most pivotal secret operations: the cracking of the German Enigma code. The episode narrates how a combination of technical brilliance, international collaboration, early computing machinery, and German operational errors led to the Allies breaching what was once considered an unbreakable cipher. Arndt gives both the Polish and British cryptographers their due credit and explores Enigma’s legacy in modern cryptography and computer science.

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Key Discussion Points & Insights

1. The Role of Cryptography in Warfare

• [02:58] The critical necessity for secure military communications has driven encryption since ancient times.
  • “Codes and ciphers have always been an important part of warfare...” (Gary Arndt, 02:58)
• The shift from physical, concealable documents to radio transmissions made robust encryption essential, as messages could be intercepted by anyone listening.

2. One-Time Pads vs. Practical Encryption Machines

• [03:23] One-time pads are theoretically unbreakable, but their limitations make them impractical for large-scale or multi-party communications.
  • “A one time pad is...guaranteed 100% unbreakable. However, there’s a catch. You can only use it once, and you really can’t use it with multiple parties.” (Gary Arndt, 03:23)

3. The Invention and Mechanics of Enigma

• [04:00] German engineer Arthur Scherbius patents and develops Enigma in 1918.
• The Enigma machine used multi-layered substitution ciphers:
  • Rotors for daily-specific settings.
  • A plugboard for additional complexity.
  • Each keypress altered subsequent substitutions, creating “a brand new letter substitution for every single character.” (05:31)
• Statistical Strength: For a 3-rotor device with plugboards, “almost 159,000,000,000 possible settings.” (06:31)

4. German Operational Security and Overconfidence

• [07:25] Germans widely adopted Enigma for high-level communications, trusted its security, and took stringent (but not infallible) steps to protect devices and codes:
  • “The protection of Enigma devices and the daily settings were a top priority... settings were actually printed on water soluble ink that would be erased if a ship were to sink.” (Gary Arndt, 07:40)

5. Polish Cryptographers' Pioneering Efforts

• [08:23] In the 1930s, Poland led early efforts to decipher Enigma.
  • Mathematician Marian Rejewski “made huge strides in understanding how it worked and weaknesses in the system.” (Gary Arndt, 08:41)
• German procedural errors—like repeated message settings—enabled cracks.
• The Polish team invented the first machine for Enigma decryption, the “bomba.”
• Escalating difficulty: Adding more rotors increased combinations from 6 to 60.

6. International Collaboration Against Enigma

• [10:06] Pre-WWII, Poles shared Enigma breakthroughs with Britain and France.
• After the German invasion, the Polish team evacuated to France (PC Bruno) and later collaborated closely with British cryptographers from Bletchley Park.
• Alan Turing worked directly with the Polish and French teams, exchanging vital methods and knowledge.

7. The British & Bletchley Park’s Triumph

• [11:08] Post-France’s fall, Alan Turing and his team at Bletchley Park built on Polish methods.
  • Developed their own “cryptographic bomb,” a brute-force device, but the breakthrough came from identifying “known phrases” in German messages.
  • Memorable Insight: “The eureka moment came when they realized that almost every message sent by the Germans ended in the exact same two: Heil Hitler.” (Gary Arndt, 12:15)
• Secrecy: The Allies had to use Enigma intelligence carefully to avoid alerting Germans.

8. Later Developments & Legacy

• Americans later joined, developing faster decryption machines.
• Enigma’s cracking wasn’t publicized until the 1970s.
• Today, original machines fetch high prices at auction—over $547,000.
• Modern Perspective: In 2017, AI cracked Enigma in under 13 minutes—but “it required the use of 2,000 cloud servers.” (Gary Arndt, 13:37)
• Turing is commemorated on the UK £50 note; the Turing Award is computer science’s “Nobel Prize.”

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Notable Quotes & Memorable Moments

• On Encryption’s Evolution:
  • “With the advent of wireless radio communications, things changed...you need to have an extremely robust encryption system.” (Gary Arndt, 03:10)
• On Enigma’s Complexity:
  • “Every time a key was pressed, it would turn the rotors, in effect creating a brand new letter substitution for every single character.” (Gary Arndt, 05:31)
• Underscoring Polish Efforts:
  • “The work done by Polish cryptographers...their work wouldn’t have been possible without the trail that the Poles had blazed in the years before the war.” (Gary Arndt, 10:52)
• The Decisive ‘Known Phrase’ Shortcut:
  • “The eureka moment came when they realized...the exact same two: Heil Hitler.” (Gary Arndt, 12:15)
• On Enigma’s Strategic Importance:
  • “Some historians believe cracking the Enigma code may have shortened the war by two years and saved over 14 million lives.” (Gary Arndt, 14:10)
• On Computing’s Future:
  • “The work done on breaking the code didn’t just help win the war, but it helped lay the foundations for modern computing and cryptography.” (Gary Arndt, 14:27)

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Timestamps for Critical Segments

• [03:10] — Why wireless communications demanded advanced cryptography
• [04:00 – 07:25] — How the Enigma machine worked and German security practices
• [08:23 – 10:52] — Poland’s breakthroughs, German procedural errors, the bomba, and collaboration
• [11:08 – 12:55] — Transition to British and American efforts, Turing’s bomb, and the critical “Heil Hitler” shortcut
• [13:37 – End] — Legacy: Modern codebreaking, Turing’s recognition, and Enigma’s role in history

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Conclusion

Gary Arndt’s episode presents a concise yet comprehensive history of Enigma, balancing technical explanation with human drama. He celebrates the crucial, often overlooked Polish contributions; details the technical, computational, and strategic efforts at Bletchley Park; and highlights the immense significance of the Enigma breakthrough on both the Allied victory in WWII and the dawn of the computer age.

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Transcript

[A]

The following is an encore presentation of Everything Everywhere Daily. During the Second World War, the Germans used what they thought to be an uncrackable encryption system and it was a really good encryption system and for the longest time the Allies had a difficult time cracking the code. However, thanks to brilliant code breakers, a powerful computing machine and German mistakes, the Allies were finally able to break the code. Learn more about the Enigma code and how it was broken on this episode of Everything Everywhere Daily.

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See Mint Mobile for details. Codes and ciphers have always been an important part of warfare. Commanders needed to give orders to units that couldn't fall into the hands of enemies. If you remember back to my episode on cryptography, cipher systems of some sort have been used since ancient history. There is evidence of some sort of encrypted writing in ancient Mesopotamia, India, Greece and Rome. For most of history, encryption was tied to a physical document. You could hide or conceal a document so the enemy wouldn't even know you had a document. However, with the advent of wireless radio communications, things changed. You could send communications quickly over long distances, but the communication could be picked up by anyone who was listening. When you know the enemy is going to have access to your encrypted communications, you need to have an extremely robust encryption system. There is a system that is extremely secure, known as a one time pad. A one time pad is a system of random characters that are shared between two parties. And the system is guaranteed 100% unbreakable. However, there's a catch. You can only use it once, and you really can't use it with multiple parties. If a central command wanted to communicate with multiple distributed units, you have to give everyone the same one time pads, and if one of them fell into the hands of the enemy, then it would be able to decrypt everything. What you wanted was a system that was difficult to crack. And if a message was cracked, it didn't mean that you could crack any previous or subsequent messages. Such a system was developed in 1918 by the German electrical engineer Arthur Scherbius. It was an electrical machine that could encrypt messages. He received a patent for his invention and sold it under the name Enigma. The Enigma machine was an extremely clever device. At its core was the oldest method of encryption in the world, letter substitution. Letter substitution systems are extremely simple. Just take a letter of the Alphabet and replace it with another letter and then write the code using the replace letters. The problem is these systems are also very easy to crack. They can be done almost instantly with a computer and they can be done rather easily by hand as well. They're easy enough to crack that they're often used as puzzles in newspapers. What was brilliant about the Enigma system, however, is that it changed the substitution after every letter. To have an understanding of how it worked, let me describe a basic Enigma machine. There were several different versions of the machine, but this basic description would apply to all of the versions. An Enigma machine was about the Size of a small cash register. At the bottom was a keyboard. Above the keyboard were rotors. Each rotor had 26 possible settings which had to be set before encrypting or decrypting a message. Depending on the version of the machine, there could be anywhere from three to eight rotors. The rotors could have been selected from a larger number of rotors, such as three out of a possible five in some machines. There was also an electrical plug board on the front just below the keyboard. For versions with the plug board, each plug corresponded to a letter of the Alphabet and multiple cables would connect multiple letters of the Alphabet together. At the top, there was a set of lights that also corresponded to each letter of the Alphabet. When a message was to be encoded, the rotors were set to whatever the predetermined settings were for that day. Likewise, if there was a plug board, those would have to be set to the preordained settings as well. The sender would type a key which would then light up one of the letters at the top. However, every time a key was pressed, it would turn the rotors, in effect creating a brand new letter substitution for every single character. The plug board added an extra layer of encryption by electronically switching letters before it was sent to the rotors. If you had a three rotor Enigma machine taken from a set of five rotors and ten letter prayers connected on the plug board, there would be almost 159,000,000,000, possible settings for the device. Decrypting the device would be doing the exact opposite. You would set the machine to that day's settings and then type in the encrypted letter which would light up the decrypted letter at the top. Every day the rotor settings would be changed according to a set schedule. So even if you could somehow decrypt a given message, it would be useless the next day because the routers would create a whole new system. If you wanted to decrypt a message, you needed an Enigma machine with the right rotors and you needed to know the settings for that message. The Germans were extremely confident in their Enigma machines. They were used at all levels of the German military and were used to transmit secrets with the highest classification. Needless to say, the protection of Enigma devices and the daily settings were a top priority in the German navy. The settings were actually printed on water soluble ink that would be erased if a ship were to sink. In the event that a ship were to be captured, the rotors were to be taken out and thrown overboard as the ship was abandoned. The first version of the Enigma machines were actually used by the German government as early as 1923, well before the Nazi party ever came to power. Over the years, various versions of the machine were rolled out to be used by various branches of the military. Attempts to break the Enigma code began well before the war started. It was truly a monumental task given the strength of the Enigma system. British cryptographers have gotten much of the attention and and more on that in a bit. But the Polish Cipher Bureau actually conducted the original work on the machines in the early 1930s. Poland had a greater and earlier incentive to crack the German code before any other European country did. Not surprisingly, the Poles had a great deal of difficulty in cracking the code. A Polish mathematician by the name of Marian Rieski made huge strides in understanding how it worked and weaknesses in the system. One of the things that he realized was that there were flaws in the German procedures. First, they used a single setting for all of the messages on a given day. And second, they put a six letter indicator with a message key at the top of every message. This was an encrypted command to tell the decrypting officer how to set their rotors. And this was done by the Germans up until 1938. This and other errors made by German operators made it possible for Rajsky to decrypt some of the messages without ever knowing the initial settings of the device. The Poles made many other advancements in cryptography in attempting to break the Enigma code and also developed one of the first machines that could work on decryption. It was called a cryptologic bomb or a bomba. The bomba was a brute force attempt at trying to solve the rotors. However, a general solution to the Enigma code eluded them. And things got worse when the Germans added two more rotors that could be used to make up the three rotors. This increased the number of rotor combinations from 6th to 60. In 1939, when it looked like war with Germany was inevitable, the Poles began to share what they had learned with Britain and France. When Germany did invade, the Polish Cipher Bureau destroyed their machines and documents and evacuated the team to the south into Romania. They wound up in France at a site called PC Bruno, where they continued their work. British cryptographers from the British Crypto Analysis Centre in Bletchley park visited P.C. bruno several times. In January 1940, one of the researchers by the name of Alan Turing came to PC Bruno to work with the Polish and French team. PC Bruno and Bletchley park worked closely together and had their own secure telegraph cable to communicate with each other. When the Germans invaded France in 1940, many of the PC Bruno team managed to flee to Britain, but some of them were actually captured. After the war, it was determined that none of the cryptographers had disclosed anything that they knew. I want to stress the work done by Polish cryptographers because much of the story of cracking the Enigma code focuses on Alan Turing and the team at Bletchley Park. While they do deserve a great deal of credit, as the team at Bletchley themselves recognized, their work wouldn't have been possible without the trail that the Poles had blazed in the years before the war. After the invasion of France, the job of cracking the Enigma code now fell to Bletchley park and the team led by Alan Turing. Turing created their own version of a cryptographic bomb. This, like the Polish version, would try to brute force all 17,576 possible settings of the wheel orders. The bomb wasn't a computer as we think of it today. It was electrical, but it was mostly mechanical. The problem was they had to do this every day with a fresh new set of intercepted codes, and they couldn't guarantee that they could break the code every day. What they needed was a shortcut, some phrase that they knew in advance that they could use to cut down on the number of possible combinations. The eureka moment came when they realized that almost every message sent by the Germans ended in the exact same two Heil Hitler. This seemingly innocuous phrase was the Achilles heel that allowed the Enigma code to be broken. Solving the known phrase Heil Hitler allowed them to decrypt the code for the day and read everything rather quickly. The Americans were eventually let in on the project when they joined the war, and the Americans built their own cryptographic bomb, which was much faster than the British version. Keeping the fact that they had cracked the Enigma code a secret was very difficult. They couldn't simply act on every bit of intelligence they had, or else it would give away the fact that they had cracked the code. They used just enough information to make the Germans think that they had gained the information from other sources, like radar or spying. Today, there are several original Enigma machines that can be found in museums around the world and in the hands of private collectors. Enigma devices have been sold at auction for as much as $547,000. And there are even replica Enigma machines that you can buy. If you're like me, you might be curious how quickly the Enigma code could be solved using modern computers. Well, in 2017, an artificial intelligence program managed to crack the Enigma code in 12 minutes and 50 seconds, and to do it that fast, it required the use of 2,000 cloud servers. Today, Alan Turing is celebrated on the 50 pound note in the UK, and the Turing Award given out by the association of Computing Machinery is considered to be the Nobel Prize in computer Science. Breaking the Enigma code was one of the most important strategic breakthroughs of the Second World War, and the public wasn't even made aware of it until the 1970s. But since it became public, the breaking of the Enigma code has become one of the most celebrated chapters in the history of the war, and the story has been told in books, movies and on television. Some historians believe cracking the Enigma code may have shortened the war by two years and saved over 14 million lives. The work done on breaking the code didn't just help win the war, but it helped lay the foundations for modern computing and cryptography. And it was all because a group of Polish and British code breakers managed to break a code that was considered to be unbreakable. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Austin Otkin and Cameron Kiefer. My big thanks go to everyone who supports the show over on Patreon.

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Your support helps make this podcast possible.

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And I also want to remind everyone about the community groups on Facebook and Discord. That's where everything happens that's outside the podcast, and links to those are available in the show notes. As always, if you leave a review on any major podcast app or in the above community groups, you too can have it read on the show.