By Evan Hatch
Compiled by | Wu Talks about Blockchain
Original link:
https://evanhatch.medium.com/len-sassaman-and-satoshi-e483c85c2b10
Preface: According to Politico, a new HBO documentary claims to have cracked the true identity of Satoshi Nakamoto, the anonymous creator of Bitcoin, but HBO's promotional materials do not explicitly state this claim. The people most often suspected of being Satoshi Nakamoto include the late software engineer Hal Finney, system engineer Dorian Nakamoto, computer scientist Nick Szabo, and Hashcash inventor Adam Back. However, Len Sassaman currently ranks first on the prediction website, far ahead of others. Who exactly is Len Sassamanv? This article provides a comprehensive description.
We have lost too many hackers who committed suicide. What if Satoshi was one of them?
In every Bitcoin node, there’s an obituary embedded in the transaction data, a memorial to Len Sassaman — a man virtually immortalized on the blockchain. It couldn’t be a more fitting memorial.
Len is a true cypherpunk — smart, fearless, and idealistic. He has dedicated his life to defending individual freedom through cryptography, has participated in the development of PGP encryption and open source privacy technology, and as an academic cryptographer, studied P2P networks under the guidance of blockchain inventor David Chaum.
He is also a stalwart of the hacker community: a friend and influencer of many important figures in information security and cryptocurrency history.
Losing Satoshi
By all accounts, Len would become one of the foremost cryptographers of his time. But on July 3, 2011, at the age of 31, he tragically took his own life after a long battle with depression and functional neurological disorder.
His death coincided with the disappearance of the world’s most famous cyberpunk — Satoshi Nakamoto. Two months before Len’s death, Satoshi sent their last communication:
I have moved on to other things and may not be around again.
After 169 commits and 539 posts in a year, Satoshi disappeared without explanation, leaving behind a pile of unfinished features, a heated debate about their vision for Bitcoin, and a $64 billion BTC fortune that remains unspent to this day.
We’ve lost too many hackers to suicide. Aaron Swartz, Gene Kan, Ilya Zhitomirskiy, James Dolan. They’ve all fallen victim to an epidemic of shame and depression that’s taking its toll on technological progress itself. Imagine if the creators of Bitcoin had died before they could finish it. If that were true, what would they have brought to the world if they’d been given the care and respect they deserve?
I hesitate to speculate on Satoshi’s identity because the discussion around this topic often ranges from misleading to ridiculous and even unethical. However, with Craig Wright falsely claiming to be the creator of Bitcoin, it is necessary to revisit this topic and put the focus back on the cypherpunks who actually built Bitcoin.
Whoever Satoshi was, they were undoubtedly “standing on the shoulders of giants” — Bitcoin is the cumulative result of decades of research and discussion in the cyberpunk community. In this sense, Len was undoubtedly an indirect contributor. But we still can’t help but ask, who wrote the code, ran the first node, and published content under the pseudonym Satoshi?
In order to synthesize and implement the many ideas that Bitcoin is based on, that individual or team must have unique expertise across multiple fields, including public key infrastructure, academic cryptography, P2P network design, practical security architecture, and privacy technology. They are likely to have deep roots in the cyberpunk community and close ties to those who have had a significant impact on cryptocurrency. Finally, they need to have ideological conviction and the hacker spirit to "roll up their sleeves" and anonymously build a real-world system that has previously remained in the theoretical realm.
When I look back at Len’s life, I see many of the same traits. I think Len was probably one of the direct contributors to Bitcoin.
As cryptocurrencies are receiving unprecedented attention, I hope this will help raise awareness of the unsung heroes we should all be grateful for. I also hope it will help us reflect on how important it is to shine a light on mental illness, especially functional neurological disorders that deserve more attention.
origin
Even at a young age, Len was a self-taught technologist who focused on cryptography and protocol development. Although he lived in a small town in Pennsylvania, at the age of 18, Len joined the Internet Engineering Task Force, which was responsible for the TCP/IP protocol, the foundation of the Internet, and later became the basis of the Bitcoin network.
Len was diagnosed with depression as a teenager, “because he was smart and always seemed a little special.” Unfortunately, he experienced traumatic treatment from a psychiatrist who was “close to abusive” during his treatment, an experience that may have left him with a deep distrust of so-called authority figures.
In 1999, Len moved to the Bay Area and quickly became a fixture in the cyberpunk community. He lived with Bram Cohen, the creator of Mojo and Bittorrent, and contributed to the legendary cyberpunk mailing list where Satoshi first announced Bitcoin. Other hackers remember him as a smart guy with a lighthearted sense of humor who chased squirrels at a cyberpunk party and drove a sports car with a "get-out-of-jail-free card" in case he was stopped by the police.
In San Francisco, Len devoted himself to defending individual freedom and privacy through direct action in technology and politics. At 21, he made headlines for organizing protests against government surveillance and for speaking out in solidarity with the imprisonment of hacker Dmitri Skylarov.
PGP
Early in his career, Len stood out as an authority on public key cryptography, the very foundation of Bitcoin. At 22, he was already speaking at conferences and co-founding a public key crypto startup with renowned open source activist Bruce Perens.
After the startup collapsed in the dot-com crash, Len joined Network Associates to help develop PGP encryption, which is essential to Bitcoin. In 2001, during the release of PGP7, Len was responsible for setting up interoperability testing of the OpenPGP implementation, which brought him into contact with many important cryptographic pioneers. Len also contributed to the OpenPGP implementation of GNU Privacy Guard and invented a new encryption protocol with Phil Zimmerman, the inventor of PGP.
When introducing Bitcoin, Satoshi said he hoped Bitcoin would become “the same thing for money” as strong cryptography (like PGP) did for file security.
Generations ago, multi-user time-sharing computer systems faced a similar problem. Before the advent of strong encryption, users had to rely on password protection…
Then, strong cryptography started to become available to the masses and trust was no longer necessary… Now, it’s time to have the same thing in the monetary space.
Hal Finney
At Network Associates, Len worked with Hal Finney on the development of PGP. Finney was the second developer of PGP and helped create RFC 4880, the OpenPGP interoperability standard. He was also the earliest and most important contributor to Bitcoin after Satoshi:
● Finney was the first person besides Satoshi to contribute to the Bitcoin code and run a Bitcoin node.
● Finney was the first recipient of Bitcoin (Satoshi personally sent it to him).
● Finney invented the concept of “Reusable Proofs of Work” on which Bitcoin mining is based.
● Satoshi communicated extensively with Finney before Bitcoin was released. In their last few exchanges, Satoshi openly expressed his respect for Finney.
Finney is unsurprisingly one of the most popular candidates to be Satoshi, even though this meant faking a lot of email interactions with Satoshi, contributing to Bitcoin under both his real and fake identities, and continuing to work for Bitcoin after Satoshi “left” in 2011.
Remailer
Len and Finney shared a very rare and relevant skill: they were both developers of the remailer technology, one of the precursors to Bitcoin.
Remailers were proposed by David Chaum along with cryptocurrency, and are specialized servers used to send messages anonymously or pseudo-anonymously. The use of remailers was common when participating in the Cyberpunk mailing list, which itself was built on top of distributed remailers.
Schematic diagram of a Type II remailer
Early remailers simply forwarded messages and masked the sender's identity, while later protocols (such as the most popular Mixmaster remailer) rely on decentralized nodes to distribute fixed-size encrypted blocks of information through a P2P network. Bitcoin's architecture is very similar to a remailer, except that its nodes transmit transaction data instead of messages. In 1997, crypto-anarchist founder Tim May even proposed a digital currency based on a remailer.
As the lead developer, node operator, and primary maintainer of Mixmaster, Len is a leading expert in remailer technology. He also implemented similar technology in the Anonymizer privacy protection project as a systems engineer and security architect.
The remailer is not only the direct predecessor of Bitcoin technology, but also the foundation of its intellectual history. In the article (Why the Remailer), Finney argues that the remailer is the foundation of the anonymous digital economy.
Remailer is the “foundation layer” of this idea — it gives us the ability to exchange messages privately without revealing our true identity. In this way, we can conduct transactions, show our credentials, and reach agreements without having to worry about government or corporate databases tracking our every move.
One of the cyberpunk visions includes the ability to conduct transactions anonymously, using “digital cash.” … This is another area where anonymous email plays an important role.
Remailer operators were among the first to realize the need for cryptocurrencies: due to the lack of anonymous payment methods, remailers had to be run at their own expense. This caused scalability issues and led to spam and abuse becoming commonplace. Because of this, the basic concepts of many cryptocurrencies stem from the need to create an abuse-resistant, for-profit remailer:
● In 1994, Finney proposed that remailers could be monetized through anonymous “coins” and “cash tokens.”
● Smart contracts were first discussed in the context of preventing abuse by remailers. Nick Szabo’s 1997 forward-thinking smart contracts paper specifically mentioned Mixmaster.
● Ian Goldberg and Ryan Lackey (two important people Len met) were major figures in the remailer community, and they developed an unfinished cryptocurrency called HINDE in 1998. Ian later created several early electronic cash clients, and Ryan became the Chief Security Officer of Tezos.
Thus, Satoshi’s second post about Bitcoin mentions “sending emails for money” as the first real use case for Bitcoin.
Initially, it can be used for nearly free proof-of-work applications.
It can already be used to send emails for a fee. The send dialog is resizable and you can enter a message of any length.
Adam Back
Among the small remailer community, Len also intersects with Blockstream CEO Adam Back — the first person to communicate with Satoshi.
Back’s interest in cryptocurrencies stemmed from operating a remailer, and he invented the HashCash proof-of-work system for remailer operators to use to combat spam and DDoS attacks. Satoshi later used HashCash as the basis for Bitcoin mining.
We know that Len worked directly with Back, who is listed as a contributor to one of Len's research papers and a Mixmaster memo. They were both involved in multiple OpenPGP implementations and were connected to each other in their PGP web of trust.
Interestingly, Back himself has suggested that Satoshi may have been a remailer developer, noting that these developers “[practice] their craft” and participate in cryptographic protocol discussions in a pseudo-anonymous manner. Unlike many of the Cyberpunk figures in the discussion, we know that Len made extensive contributions to the Cyberpunk mailing list in a pseudo-anonymous manner via a remailer.
Chaum and COSIC
After graduating from high school, Len worked to support his family and never had the opportunity to attend university. However, in 2004, he successfully obtained his "dream job" as a researcher and doctoral candidate at the Computer Security and Industrial Cryptography Research Group (COSIC) at K.U. Leuven in Belgium.
At COSIC, Len’s doctoral advisor was none other than David Chaum, the “Father of Digital Currency.” Although Chaum laid the foundation for the entire cyberpunk movement and all cryptocurrencies, few people can claim to have worked directly with him.
Chaum's several notable achievements include:
● Invented cryptocurrency in the 1983 paper (Blind Signatures for Untraceable Payments).
● Invented blockchain in his 1982 PhD thesis, which described all elements of the blockchain in the Bitcoin white paper except one.
● He founded Digicash, the first electronic cash system, with anonymous payments between digital avatars as its core vision.
“[Chaum] is at the center of a seemingly unstoppable movement — the digitization of money…The wild card in the age of digital money is anonymity, and David Chaum argues that without it, we’re in trouble.”
While Digicash failed (in part due to its reliance on a centralized system), Chaum wanted to create a second digital currency that could provide both anonymity and utility.
Although many viewed its failure as proof that digital cash was unworkable, Satoshi defended the “old Chaum currency” while acknowledging the concerns posed by centralization issues.
Many people automatically dismiss cryptocurrencies as hopeless because all the companies involved have failed since the 1990s. I hope it’s clear that those systems failed simply because of their centralized nature.
Len's Research
Len worked at COSIC in Belgium until his death in 2011. During this time he amassed a distinguished record of 45 publications and 20 conference committee positions.
Len's research focuses on developing privacy-enhancing protocols with "real-world applicability" and writing actual code. His main project is Pynchon Gate, a collaboration with Bram Cohen, an evolution of the remailer technology that enables pseudo-anonymous information retrieval through a distributed network of nodes without the need to trust a third party.
Pynchon Gate and Meta Index + Bucket Pool Architecture
This project is closely related to Bitcoin — as research on Pynchon Gate progressed, Len gradually focused on solving the Byzantine problem, one of the main obstacles to early P2P networks.
Schematic diagram of the Byzantine problem
In the context of distributed computing, Byzantine fault tolerance refers to the ability of a network to remain functional even when nodes are compromised or unreliable. The Byzantine problem is one of the biggest issues that needs to be solved to ensure that cryptocurrency systems can be secure and decentralized without double spending or trusting third parties. Satoshi's most important innovation was to successfully solve this problem by introducing the blockchain proposed by Chaum, which proposed a "triple-entry accounting" system.
During the development of Bitcoin in 2008–2010, Len became increasingly active in the field of financial cryptography. He joined the International Financial Cryptography Association and gave presentations and served on the committee of the Financial Cryptography and Data Conference, which was founded by Robert Hettinga, an early advocate of digital cash, and where digital cash was one of the main topics of discussion.
Satoshi as a scholar
Many clues suggest that Satoshi may have been working in academia during the development of Bitcoin, a view supported by Gavin Andersen, founder of the Bitcoin Foundation.
“I think he’s an academic, maybe a postdoctoral researcher, or a professor who doesn’t want to draw attention to himself.”
Satoshi's code contributions and comments increased significantly during the summer and winter holidays, but decreased significantly during the late spring and final exam period at the end of the year, which is consistent with academics having more time during the holidays and being busy with exams or grading at the end of the semester.
The unique structure of Bitcoin’s code also suggests that Satoshi had an academic background. The code has been described as “brilliant but not rigorous”, lacking conventional software development practices like unit testing, but showing cutting-edge security architecture and a deep understanding of academic cryptography and economics.
This person has a deep understanding of cryptography… They’ve read the academic papers, have a sharp intellect, and combined these concepts in a really innovative way.
When renowned security researcher Dan Kaminsky first reviewed Satoshi’s code, he attempted to perform a penetration test on it using 9 different vulnerabilities, but to his surprise, Satoshi had already anticipated and patched these issues.
"I designed beautiful exploits, but every time I attacked the code, there was a line in the code that dealt with it... I've never seen anything like it."
This may indicate that Satoshi and Kaminsky shared similar information security experience and expertise. Coincidentally, Len and Kaminsky co-authored and published a paper demonstrating methods for attacking public key infrastructure.
Additionally, the Bitcoin whitepaper was published in a format not often seen on the cypherpunk mailing lists — it was a LaTeX-formatted research paper with academic touches like an abstract, conclusion, and MLA citations. This contrasted with the irregular blog post style of other proposals, such as Bitgold and b-money.
Satoshi in Europe
Since COSIC is based in Leuven, Len lived in Belgium during the development of Bitcoin. This is important because some facts suggest that Satoshi may also be in Europe, which was also the main focus of the early investigation (by the New Yorker).
Satoshi’s writing style features typical British English spellings and words such as “bloody difficult,” “flat,” “maths,” “grey,” and the dd/mm/yyyy date format. However, Satoshi also mentioned the Euro instead of the British Pound.
The Bitcoin genesis block also contains a headline from that day’s edition of The Times (“The Times, 3 January 2009: Chancellor on brink of second bank bailout”). The headline refers specifically to that day’s print edition, which is only distributed in the UK and Europe. In 2009, The Times was a top ten newspaper in Belgium and is widely used by academics and researchers due to its wide availability in libraries and detailed indexing system.
These clues present a paradox: they suggest that Satoshi was European, but the people with the skills needed for Bitcoin and access to its major influencers are more likely to be American. Most of the conferences and meetups in the cyberpunk community are concentrated in the United States, especially San Francisco, so many important figures are from the United States. Job opportunities that can gain experience in cutting-edge information security and cryptography are also mostly concentrated in the United States.
Oddly enough, even though Len is American, he uses British English exactly like Satoshi.
Analysis of Satoshi’s posting history shows that he was a European “night owl” who usually worked on Bitcoin development after finishing work or school during the day. At one point, Satoshi mentioned that the increase in mining difficulty happened “yesterday,” which would obviously not be true if he lived in the United States.
Assuming Satoshi's life was more than just Bitcoin, he would have been away from his computer at home during the day when he was working or studying... If Satoshi lived in the British Summer Time (BST) time zone, he would have mostly worked at night, often until the early hours of the morning.
When we look at Len’s tweet history, we can see that Satoshi’s posting times and code submission times are very close to when Len was active late at night.
P2P Network
While Bitcoin was not the first cryptocurrency, it was the first cryptocurrency based on a fully P2P distributed network. Satoshi emphasized this point when he first mentioned Bitcoin:
I have been developing a completely new electronic cash system that is completely peer-to-peer and does not rely on any trusted third party.
Dan Kaminsky said that to build Bitcoin, Satoshi had to "understand economics, cryptography, and P2P networks," and Len had unusually early exposure to and deep understanding of all three and their applications in digital currency.
Bram and Len at the CodeCon interview
While in San Francisco, Len lived and worked with Bram Cohen, the creator of the P2P protocol BitTorrent. Between 2000 and 2002, Bram developed a revolutionary P2P network called MojoNation that used "Mojo Tokens" as digital currency, making it one of the first publicly released digital currencies.
In MojoNation’s P2P economy, tokens can be exchanged for file storage, which is encrypted and encoded into “blocks,” uploaded to a distributed network of nodes, and recorded on a public ledger, similar to Bitcoin’s distributed bilateral accounting system. Mojo is not just an internal accounting token, but a full currency — exchangeable for US dollars and vice versa. Some of the earliest token economic discussions centered around the mechanics of the Mojo token.
A Mojo represents a portion of the overall capacity of the current system. If you work for me now, I will give you credits, and in the future when the network gets bigger, these credits will represent a portion of a bigger pie, so their value will increase as you use them.
Satoshi discussed token economics in a similar way:
It has the potential to form a positive feedback loop; as the number of users increases, the value rises, which may attract more users to take advantage of this increased value.
Despite MojoNation’s vision, its economic system quickly collapsed due to hyperinflation. Satoshi deliberately designed Bitcoin to avoid this fate, ensuring its stability through built-in deflation mechanisms and not relying on a centralized “coin minting” server.
In 2001, Bram launched BitTorrent. As a P2P alternative to Napster, BitTorrent foreshadowed Bitcoin’s own distributed node topology, consensus system, and protocol-level incentives. BitTorrent not only innovated networks like Gnutella technically, but also drove design through economic incentives and game theory.
BitTorrent design compared to Napster
Presciently, Len once told Bram, “BitTorrent will make you more famous than [Napster founder] Sean Fanning.” Satoshi would later reference Napster to explain the need for a fully decentralized web.
Governments are good at cutting off the "heads" of centralized networks like Napster, but pure P2P networks like Gnutella and Tor seem to be able to sustain themselves.
Coincidentally, Len and Tor founder Roger Dingledine both participated in the development of the Mixminion remailer protocol. The two also presented together at the Black Hat conference and co-founded the HotPETS conference.
In 2002, Len and Bram co-founded a conference called CodeCon, which focused on "projects with actual operational code." At CodeCon in 2005, Finney demonstrated "Reusable Proof of Work" (RPOW) through a modified BitTorrent client that could send P2P digital currency. One commentator described it as:
…the world’s first transparent server, which facilitates a distributed, cooperative world of RPOW servers.
Cryptocurrencies were a big theme at the inaugural CodeCon, which also featured Adam Back’s HashCash and Zooko’s demonstration of Mnet, a fully open-source and decentralized successor to MojoNation. MojoNation is not dependent on a single company and can be independently audited, both features Satoshi considered crucial.
Screenshots of the Mnet client
MojoNation co-founders Zooko Wilcox and Jim McCoy are also influential in the cryptocurrency space. Zooko was one of Satoshi’s early collaborators and worked for David Chaum’s Digicash. Satoshi also linked Zooko’s blog on Bitcoin.org when Bitcoin v0.1 was released. Zooko later founded the privacy-focused cryptocurrency Zcash and proposed the much-discussed “Zooko’s Triangle” framework.
The “Zooko Triangle” is a trilemma regarding three desirable properties of names for participants in network protocols
McCoy is also a major influencer in the cryptocurrency space, with Ryan Selkis of Digital Currency Group even stating that he believes McCoy could be Satoshi.
Hacktivism
Even by the standards of the cyberpunk community, both Len and Satoshi displayed particularly strong ideological convictions and a strong commitment to open knowledge.
I wish you guys would stop talking about me... maybe focus on the open source projects and give more recognition to the developer contributors.
Satoshi’s “hacktivist” approach to distributing Bitcoin through a free, open-source grassroots project stood in stark contrast to their predecessors. Chaum, Stefan Brand, eCash, and others took a completely different approach: filing patents, creating closed-source venture capital firms, and trying to drive adoption through corporate partnerships.
This approach has similarities to Len's own extensive contributions to open source projects, such as his contributions to projects such as PGP, Mixmaster, and GNU Privacy Guard, as well as his volunteer work in organizations such as the Shmoo Group.
Regarding this story, Bram said that Len has a preference for anonymous posting.
Satoshi alluded to their ideological leanings in several remarks, stating that Bitcoin was “very attractive” to libertarian perspectives and that it could “win a major battle in the arms race and gain years of new territory for liberty.”
Len is equally passionate about defending open knowledge and technological progress against interference from corporations and governments.
The pursuit of knowledge is a fundamental part of being human. Any kind of ex ante restriction, I think, is an infringement on our freedom of thought and our freedom of consciousness. So not only do I want us to avoid overly restrictive reactive legislation… I also don’t want to see anyone build frameworks that could be misused.
ending
Just as Satoshi created Bitcoin behind a pseudonym, Len was somewhat forced to live behind his own mask. After an incident in 2006, Len began to suffer increasingly severe non-epileptic seizures and functional neurological problems, which exacerbated the depression he had been battling since his teenage years.
As a victim of stigma, Len “felt like he had to maintain this facade of being this super-able guy,” and he was “terrified” that his failing health would end his work and disappoint the people he cared about.
Despite these challenges, Len continued to work, write papers, and even gave a lecture at Dartmouth College until a few months before his death. Sadly, he managed to hide the severity of his condition from almost everyone.
"Very few people knew it had come to this point... One thing I heard over and over again was, 'We never knew, it looks like he's OK.'"
Len speaking at Dartmouth shortly before his death
Just as Len built on the ideas of those who came before him, we sensed his commitment to building something that would transcend his own, which is one reason for his dedication to open source and open knowledge.
“This is our legacy. This research, these ideas, are leading us to knowledge never before available in human history. We are going to pass this on to future generations. We have to make sure we don’t get pushed into a corner where we can’t distribute our research to others, that it doesn’t get locked up in the vaults of intellectual property lawyers.”
Len’s death in 2011 was a huge loss for the cyberpunk and tech communities as a whole, as reflected in the outpouring of memories and condolences that followed. One in particular stood out to me: a post on Hacker News by user “pablos08”.
“Len and I became friends and were once co-creators of cyberpunk, which was a wild frontier at the time. We reimagined our world with cryptographic systems that would use math to defend the freedoms we cherished. Anonymous remailers to protect speech from the threat of retaliation; Onion Routers to ensure that no one could censor the internet; digital cash to support a radically free economy. We designed plans to decentralize and distribute everything.
We imagine complex and obscure threats to problems we might face someday; we build future protocols to protect against those threats. It's all a highly academic, geeky utopian exercise. And I usually keep it that way, but Len wants to really get involved.
Cyberpunks write code.”
