Bitcoin
How Dwork & Naor Created Proof-Of-Work In 1993
No, It Wasn’t Adam Back…
Adam Back is the co-founder and CEO of Blockstream, a for-profit company based in Canada responsible (by many) for the corporate take-over of Bitcoin.
Gregory Maxwell, Pieter Wuille, Matt Corallo, Mark Friedenbach, Luke Dash Jr, and many more Bitcoin devs are (or were in the past) associated with Blockstream, either as founding members or under a payroll as employers of this company.
Blockstream is often accused of the corporate takeover of Bitcoin development, centralizing its development and substituting previous developers (Satoshi trusted for Bitcoin code development) from core positions by canceling their GitHub privileges.
It was late 2013 with Bitcoin’s price skyrocketing, when Adam Back appeared in bitcointalk with this post: “ who is this annoying Adam Back guy?” immediately hinting he wasn’t there just for the discussion part, but would actively engage with Bitcoin’s developments.
As far as that goes the bitcoin paper cites the hashcash paper for the proof-of-work, and uses it with small changes (not all of them positive).
Adam Back (2013) ( source)
Satoshi referenced Adam Back for hashcash, a method proposed by Back to counter email spam and DoS attacks.
Hashcash was announced by Adam Back in 1997, yet the release of the paper was in 2002.
Was Adam Back the inventor of proof of work? Did he base his work on another paper, which only referenced years later, while denying knowledge of it? Was Satoshi aware of the academic papers released years before hashcash?
Is Hashcash (1997), A Reworded Version of “Pricing via Processing or Combatting Junk Mail” (1993)?
While hashcash is considered the precursor to Bitcoin’s Proof Of Work algorithm, some researchers started digging deeper and found that perhaps Adam Back’s work on PoW method of combating email spam, was already in academia since 1993. A slightly different approach, yet some in the cryptographic community have mentioned hashcash as just a reworded version of previous work by academics Cynthia Dwork and Moni Naor.
Adam Back was mentioned by Satoshi in the whitepaper, and there had been communications (emails are not publicized by Back) between the two, before the announcement of Bitcoin’s whitepaper. Adam Back also pointed Satoshi to Wei Dai, where Satoshi explains the communication with Back. The emails between Satoshi and Back were never publicized, unlike the emails between every other person Satoshi approached.
The concept was invented by Cynthia Dwork and Moni Naor in 1993 as a way to deter denial-of-service attacks…The term “proof of work” was first coined and formalized in a 1999 paper by Markus Jakobsson and Ari Juels
(Source: Wikipedia)
Proof of Work is the consensus concept used by all forks of Bitcoin (BTC, BCH, BSV). However, there is a misrepresentation of hashcash as the first paper explaining the concept of proof of work, since the same concept is described in the work by computer scientists: Cynthia Dwork and Moni Naor since 1993 (the year of the release of the academic paper).
With Naor she also first presented the idea of, and a technique for, combating e-mail spam by requiring a proof of computational effort, also known as proof-of-work a key technology underlying hashcash and bitcoin.
Source: Wikipedia
Pricing via Processing or Combatting Junk Mail
( Source, by Cynthia Dwork and Moni Naor.)
Hashcash for many cryptographers and researchers is an application based on the idea of this previous work, yet it didn’t succeed in its initial purpose to combat e-mail spam. With Bitcoin, though, and the mention on the whitepaper, it gained recognition.
Saylor Academy (saylor.org) as one would have imagined belongs to Michael Saylor (CEO of Microstrategy and Bitcoin (BTC) evangelist.
It also contains a reference to the work of Dwork and Naor:
While Dwork and Naor did not propose the term, the type of solution they introduced would become known as a “proof of work” system. Users would have to literally show that their computer performed work, to prove that they spent real-world resources.
A nifty solution, but perhaps too far ahead of its time. The proposal never made it very far beyond a relatively small circle of computer scientists.
Source: Saylor Academy
The content is striving to explain the facts, de-emphasizing the previous solution, and explaining the idea was floating, and Back was shouting out loud about it in the cryptographers’ mailing list. Yet, still, the same idea was proposed by Dwork and Naor at the beginning of the 90s, not in the mid-1990s:
Like many, Back was not aware of Dwork and Naor’s proof-of-work proposal. But by the mid-1990s, he was thinking of similar ideas to counter spam, sometimes “out loud” on the Cypherpunks mailing list.
Source: Saylor Academy
So, at this point, we have to trust Back, when he declares he wasn’t even aware such work already existed before his hashcash claims.
I had a look and their approach is very similar to that of hashcash. ( source)
It is not hashcash that looks very similar to a previous publication according to Back, but the work that was created five years ago looks very similar to that of hashcash.
Seems like a time paradox, and just from the beginning, the explanation seems to be raising even more suspicions.
The correct phrase by Adam Back should probably have been:
My work “hashcash” looks very similar to the concept this document suggests which was released five years before my invention. I haven’t referenced it, yet, but will do so since the approach is different but the fundamentals are the same.
Back went on by explaining the differences between the two concepts, defending the originality of his work.
From a technical aspect, there are differences. The main issue is the proof of work, though, as a method to combat spam, which is clearly described in Dwork and Naor’s paper.
Adam Back has repeatedly inferred and directly stated that Bitcoin is using hashcash.
“bitcoin is hashcash extended with inflation control”
Adam Back (source)
Back clearly wants hashcash to look completely original without being based on any previous work, and also wanted Bitcoin to seemingly be based on his invention (hashcash).
“bitcoin hashcash link, better explanation of the relationship between hashcash, rpow & bitcoin”
Adam Back, Wikipedia contribution (Oct, 2012)
“not sure why someone deleted, please stop! re-add bitcoin use casehashcash is more widely known for its use in bitcoin than for email spam at this point”
Adam Back- Wikipedia contribution (Jan, 2015)
The association of hashcash with Bitcoin was a main concern of Adam Back since 2012, according to the above Wikipedia proposed edits by… Adam Back.
Blockstream
Interestingly, Adam Back co-founded Blockstream in 2014 and proceeded with an aggressive strategy of confrontation, and censorship of different opinions in the Bitcoin community since that moment, with the use of one key segment, Theymos.
Theymos is an anonymous individual, Blockstream approached, since it identified the importance of controlling information within the Bitcoin ecosystem.
Theymos proceeded by limiting the visibility of arguments from the side that promoted on-chain scaling while adopting the logic of censoring opposition on r/bitcoin and bitcointalk (sites under Theymos administration).
Theymos stance was difficult to understand, yet researchers found an interesting link between Theymos and Blockstream, on an event that is barely ever discussed and buried within the realms of bitcointalk (source1, source2).
Satoshi and the email exchange with Back
Adam Back was referenced by Satoshi in the whitepaper. Adam Back was a popular cryptographer in the cyphers camp, and reasonable became one of the first cryptographers Satoshi contacted.
He is also suspected by some researchers to be Satoshi (or part of a team under this alias). His past and his approach to Bitcoin, his academic background, and the use of “double-space” make Adam Back a possible candidate.
Although, any Satoshi thesis made so far, hardly offers any substantial evidence. As with all other names presented to be Satoshi “suspects”, Back is clearly enjoying the association, however, he categorically denied any involvement with Bitcoin earlier than his first appearance in 2013.
Satoshi perhaps did not know of any similar to “Back’s” hashcash work, however the same is difficult to tell about Back.
Satoshi contacted Adam Back before the announcement of the Bitcoin whitepaper, with emails that were never made public.
Certainly, these emails contain information that fits Adam Back to keep private, otherwise, he would have made them public already.
It is the one piece required to solve the Satoshi puzzle, but may also contain more information that Adam Back later used for his purposes and plans with Bitcoin.
In Conclusion
There is no accusation in this post against the work of Adam Back but references instead.
There is a correlation concerning the core idea behind both papers, yet, the methodology Adam Back used is slightly different. Equally different is the use of Hashcash within Bitcoin’s Proof of Work.
Many questions arise though. From the hashcash “invention” to the sudden appearance of Back in Bitcoin in 2013 (paving the way since 2012) and the attempt to bear a resemblance between Bitcoin’s PoW consensus and hashcash, almost claiming Bitcoin is his invention. Not to mention Blockstream, Theymos, and the Bitcoin Core devs that rallied behind Blockstream, supporting what is widely considered a corporal hijack of Bitcoin that left it crippled on-chain and unable to scale.
Back has referred to HashCash as the beginning of proof-of-work (PoW), yet Pow was already documented in the 1993 work of Cynthia Dwork and Moni Naor. After this was noticed by researchers, the response by Back was not convincing at all. The response doesn’t change anything, though.
PoW (or Proof of Work) definitely has its roots in 1993 with Cynthia Dwork and Moni Naor and not 1997 with Adam Back’s version of hashcash. The cryptocurrency community is often misled by narratives and driven by speculation, enough to miss the point.
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