I just came across an interesting discussion topic—speculation about the true identity of Bitcoin’s creator. Recently, an HBO documentary claimed to have cracked the mystery of Satoshi Nakamoto’s identity. Although who exactly it was remains disputed, the top candidate on prediction websites is Len Sassaman, far ahead of other contenders. Many people may not have heard of this name, but his story is worth knowing.

Speaking of Len Sassaman, this guy was a true cypherpunk—smart, fearless, and idealistic. He devoted his whole life to protecting personal freedom through cryptography, took part in the development of PGP encryption and open-source privacy technologies, and studied P2P networks under the guidance of digital currency pioneer David Chaum. In hacker communities, he was also a legendary figure, with connections to many major personalities in the history of information security and cryptocurrency.

But on July 3, 2011, at the age of only 31, Len Sassaman chose to leave the world after enduring long-term depression and functional neurological disorders. Coincidentally, the timing of his death nearly matches the time when Satoshi disappeared. Two months earlier, Satoshi posted his final message: "I have moved on to other things, and may not appear again." After that, there was complete silence—leaving behind a pile of unfinished code, fierce debates about Bitcoin’s vision, and BTC worth $64 billion that still remains untouched to this day.

We have already lost too many hackers to suicide caused by depression. Aaron Swartz, Gene Kan, Ilya Zhitomirskiy, James Dolan... they all became victims of the depression epidemic that plagued the tech world. Imagine what might have happened if Bitcoin’s founder had left before completing it.

As for why Len Sassaman is listed as the most likely candidate for Satoshi, it comes down to his technical background. This guy had deep expertise in cryptography, public key infrastructure, P2P network design, practical security architecture, and privacy technology. He was largely self-taught and joined the Internet Engineering Task Force at 18, working on TCP/IP protocol development—this thing is the foundation of the internet, and later also the foundation of the Bitcoin network.

In 1999, Len Sassaman moved to the Bay Area and quickly became a core figure in the cypherpunk community. He lived with BitTorrent founder Bram Cohen and was active in that legendary cypherpunk mailing list—where Satoshi first announced Bitcoin. Other hackers remember him as a clever and humorous guy, even chasing squirrels at cypherpunk parties.

What’s crucial is that Len Sassaman’s contributions to PGP encryption development were substantial. While working at Network Associates, he developed PGP together with Hal Finney (Bitcoin’s first contributor). He also took part in the OpenPGP implementation of GNU Privacy Guard, and even designed new encryption protocols with Phil Zimmerman, the inventor of PGP. And Satoshi once said he hoped Bitcoin’s role in money would be like strong encryption (such as PGP) plays for file security.

There’s another interesting detail: Len Sassaman and Finney were both developers of remailer technology. What is a remailer? Simply put, it’s a server used to send messages anonymously or pseudonymously—an immediate predecessor of Bitcoin. Len was the lead developer and main maintainer of the Mixmaster remailer. The architecture of this technology is remarkably similar to Bitcoin’s—both transmit data through a P2P network; the difference is that Bitcoin transmits transaction data rather than messages.

In 2004, Len Sassaman finally got the opportunity he had been dreaming of—becoming a researcher and doctoral candidate in the COSIC research group at KU Leuven University in Belgium. His doctoral supervisor was David Chaum, the man often called the "father of digital currency." Chaum proposed the concept of cryptographic money as early as 1983, and in his 1982 doctoral thesis he described all the elements of blockchain—except one. What does that mean? By combining Chaum’s ideas with his own innovations, Satoshi filled in that final missing piece.

During his time in Belgium, Len Sassaman focused on developing privacy-enhancing protocols with "real-world application value." His main project was Pynchon Gate—an evolution of remailer technology co-developed with Bram Cohen—which enabled pseudo-anonymous information retrieval through a distributed node network without needing to trust third parties. How deep was the relationship between this project and Bitcoin? As the research went deeper, Len gradually shifted his focus to the Byzantine problem—which was one of the major obstacles in early P2P networks, and also key to ensuring the security and decentralization of cryptocurrency systems.

Here’s another fascinating detail: analysis of Satoshi’s posting history suggests he was a European "night owl." He typically developed Bitcoin only after working or finishing studying during the day. Although Len Sassaman was American, the English he used was British English—exactly the same writing style as Satoshi’s. Both used phrases like "bloody difficult," "flat," and "maths," as well as the dd/mm/yyyy date format. Even the genesis block of Bitcoin quoted that day’s headline from The Times—a newspaper mainly circulated in the UK and Europe, especially common in Belgian academia.

From a technical depth perspective, building Bitcoin requires understanding economics, cryptography, and P2P networks—Len Sassaman had unusually early exposure and a deep understanding in all three. Alongside Bram Cohen, he witnessed the rise and fall of MojoNation, one of the earliest publicly released digital currencies, which used Mojo tokens as the foundation for a P2P economy. Len saw the lesson of how it collapsed due to hyperinflation, and Satoshi clearly learned from the same lesson. When designing Bitcoin, Satoshi intentionally built in an embedded deflationary mechanism to ensure stability.

One more detail: Len Sassaman and Tor founder Roger Dingledine both participated in developing the Mixminion remailer protocol, and the two even gave a joint presentation at Black Hat. In 2002, Len and Bram co-founded the CodeCon conference, focusing on "projects with working, runnable code." At the 2005 CodeCon, Finney demonstrated an improved BitTorrent client that could send P2P digital currency—described as "the world’s first transparent server, promoting a distributed, cooperative RPOW server world."

From an ideological perspective, both Len Sassaman and Satoshi demonstrated an especially strong conviction and commitment to open knowledge. Len contributed many open-source projects and did volunteer work. He once said, "The pursuit of knowledge is a fundamental part of humanity. Any prior restrictions, I believe, are an infringement on our freedom of thought and consciousness." And Satoshi chose to distribute Bitcoin through free, open-source grassroots projects—completely different from the patent-and-venture-capital route that people like Chaum and Stefan Brand took before him.

Finally, the story is a bit heavy. After an incident in 2006, Len Sassaman began experiencing increasingly severe seizures and functional neurological problems, which worsened the depression he had started having since his teenage years. As a victim of stigma, he "felt he had to maintain a superpower-like facade" and "was afraid" that his worsening health would ruin his work and disappoint the people who cared about him. Even so, he kept working, kept writing papers, and even gave a lecture at Dartmouth a few months before his death. But he managed to hide the severity of his condition from almost everyone.

On Bitcoin’s blockchain, there is a transaction with an embedded obituary—that’s the most fitting tribute to Len Sassaman. In this way, he is forever inscribed in the system he may have helped create. We have lost too many talented hackers to suicide. If Len Sassaman and these other pioneers had received the care and respect they deserved, what would they have brought to the world? That’s a question worth reflecting on.