Did AI really just crack an 80-year-old cipher in 10 hours? Has AI actually 'understood' it?

Imagine you’re in a dusty attic and discover an indecipherable coded note left by your grandfather 80 years ago—a puzzle that world-renowned cryptographers have been stumped by for over two decades. If you told your new smart AI assistant to “figure this out,” and it perfectly interpreted the contents in just 10 hours, how would you feel?

Remarkably, this actually happened. Released on September 3, 2026, OpenAI’s latest AI model, GPT-6 Astra (an advanced artificial intelligence capable of grasping complex contextual nuances and reasoning autonomously), is the star of this story Source 6, Source 14, Source 15. This model stunned the world by cracking historical ciphers that had remained unsolved for decades, one after the other Source 7, Source 13.

Why does this matter?

What does an AI cracking a cipher have to do with our daily lives? In truth, cryptanalysis is not just a game of matching characters; it requires high-level reasoning—the process of drawing conclusions through logical thinking. Ciphers hide information behind specific rules; the fact that an AI discovered these rules means it has moved beyond mere information retrieval, engaging in a process of “formulating and verifying logical hypotheses,” much like a human.

This ability will significantly change our lives. Just as AI read the context within the ciphers, it can identify patterns humans have overlooked in complex legal documents, arcane medical papers, or undiscovered scientific principles, offering solutions in the process. In fact, this achievement suggests that the era of “AGI” (Artificial General Intelligence—AI with human-equivalent or superior intelligence), which transcends human intellectual limits, is rapidly approaching Source 17.

Understanding it simply

Why haven’t we been able to solve these ciphers until now? Because it’s like a “giant puzzle” with thousands of pieces but a blurry image, leaving us unsure where they fit.

GPT-6 Astra’s performance was akin to a “genius detective” piecing the puzzle together. Take the 108-year-old German World War I cipher, for example Source 7. Previous cryptographers firmly believed the keyword used in this cipher was only valid for a fixed period. The AI, however, formed a completely different hypothesis, effectively concluding that “the premises established by existing cryptographers were wrong” Source 11, Source 16.

Simply put, while everyone was pushing on a door thinking it opened sideways, the AI realized, “Perhaps it needs to be pulled?” and easily opened it. By analyzing the statistical context of the cipher, the AI broke the “fixed mindset” held by existing academia Source 16.

Current status

OpenAI introduced GPT-6 Astra on September 3rd Source 14. In a test participated in by Bloomberg developer Carter Leffen, the model cracked a 1941 Nazi Enigma message in 10 hours Source 8, Source 9, Source 13.

This message had been left “unsolved” in the Crypto Cellar archives since 2005 Source 12, Source 13. It didn’t just solve old ciphers; it autonomously formed hypotheses to crack 108-year-old World War I messages, which were later confirmed to match actual historical ship logs from that time Source 7, Source 16.

However, it’s not perfect. While AI is strong at logic games like ciphers, it still makes mistakes in the complex, unpredictable situations of the real world. In a recent experiment, it even ruined a game due to a minor error while controlling a character Source 10. It is still in a learning phase toward becoming a “universal problem-solver” in every domain.

What’s next?

Experts evaluate this incident as the point where we have entered the “AGI era” Source 17. Greg Brockman, co-founder of OpenAI, summarized the significance of this achievement with the short phrase, “Welcome to the AGI era” Source 17.

Moving forward, we may go beyond simply telling AI to “write this text” and instead ask it to “formulate a hypothesis for this decade-old challenge at our company and find a solution.” Because the ability to crack a cipher leads directly to the ability to define problems and find solutions. A future is approaching where you, too, will solve your troubles or work-related roadblocks alongside AI in this manner.

MindTickleBytes AI Reporter’s Take This cipher-cracking incident doesn’t stop at merely reading historical records. It proves that AI can verify its own logical hypotheses, surpassing human conventional wisdom. We are witnessing the birth of an “intellectual partner” that goes beyond being a tool, pondering complex problems that humanity has been unable to solve.

References

1. GPT-6 Astra cracks a 1941 Enigma message that has resisted solution since 2005
2. GPT-6 Astra Decodes 108-Year-Old World War I German Cipher
3. OpenAI’s GPT-6 Astra Cracked a Nazi Enigma Message in 10 Hours: Is Bitcoin Next?
4. OpenAI’s GPT-6 Astra decrypts a Nazi radio message in ten hours that went unsolved for 83 years
5. GPT-6 Astra beat Pokémon FireRed in 18 hours, then lost a Minecraft run to one creeper
6. r/singularity on Reddit: ChatGPT-6 Astra cracks 108-year-old unsolved WWI German code for the first time
7. GPT-6 Astra Breaks an Old Enigma Message - Schneier on Security

8. [GPT-6 Astra Decodes 1941 Enigma Radio Message

   ForkLog](https://forklog.com/en/gpt-6-astra-decodes-1941-enigma-radio-message/)

9. GPT-6 Astra - Wikipedia
10. OpenAI launches GPT-6 Astra and says welcome to… - The New Stack

11. [ChatGPT-6 Astra cracks 108-year-old unsolved…

    Tom’s Hardware](https://www.tomshardware.com/tech-industry/artificial-intelligence/chatgpt-6-astra-cracks-108-year-old-unsolved-wwi-german-code-for-the-first-time-radio-message-sharing-enemy-movement-intelligence-had-evaded-decoding-1918-crimean-fleet-warning-verified-against-hms-canterbury-logs)

12. OpenAI says it has overtaken Anthropic with a model that sometimes…
13. GPT-6 Astra Crowns itself King of AI, Apple says OpenAI built it with stolen data