Satoshi Nakamoto:

From: "Satoshi Nakamoto" <satoshi@anonymousspeech.com> Sent: Friday, August 22, 2008 4:38 PM To: "Wei Dai" <weidai@ibiblio.org> Cc: "Satoshi Nakamoto" <satoshi@anonymousspeech.com> Subject: Citation of your b-money page I was very interested to read your b-money page. I'm getting ready to release a paper that expands on your ideas into a complete working system. Adam Back (hashcash.org) noticed the similarities and pointed me to your site. I need to find out the year of publication of your b-money page for the citation in my paper. It'll look like: [1] W. Dai, "b-money," http://www.weidai.com/bmoney.txt, (2006?). You can download a pre-release draft at http://www.upload.ae/file/6157/ecash-pdf.html Feel free to forward it to anyone else you think would be interested. Title: Electronic Cash Without a Trusted Third Party Abstract: A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without the burdens of going through a financial institution. Digital signatures offer part of the solution, but the main benefits are lost if a trusted party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as honest nodes control the most CPU power on the network, they can generate the longest chain and outpace any attackers. The network itself requires minimal structure. Messages are broadcasted on a best effort basis, and nodes can leave and rejoin the network at will, accepting the longest proof-of-work chain as proof of what happened while they were gone. Satoshi

The title does not mention Bitcoin, and the abstract is not identical to the final one, which is slightly better written (eg no “broadcasted” typo); a word-level diff of the abstracts using Mergeley.com :

Old/new differences in abstract

The bit about Adam Back has been mentioned before; on 2013-04-18, Adam Back posted to the BitcoinTalk forums a self-introduction mentioning that

…So anyway I know a few things about ecash, privacy tech, crypto, distributed systems (my comp sci PhD is in distributed systems) and I guess I was one of the moderately early people to read about and try to comprehend the p2p crypto cleverness that is bitcoin. In fact I believe it was me who got Wei Dai’s b-money reference added to Satoshi’s bitcoin paper when he emailed me about hashcash back in 2008. If like Hal Finney I’d actually tried to run the miner back then, I may too be sitting on some genesis/bootstrap era coins. Alas I own not a single bitcoin which is kind of ironic as the actual bitcoin mining is basically my hashcash invention…

The “pre-release draft” link is now broken. I have tried to refind it:

the original fly-by-night filehosting site disappeared years ago, and does not appear to have been renamed or moved

the filehosting download page & PDF are unavailable in the Internet Archive

are unavailable in the Internet Archive the earliest version of the whitepaper on Bitcoin.org in the Internet Archive is a later draft, using the name “Bitcoin” (unsurprisingly); looking at the full list of mirrored files for that domain, there don’t appear to be any other PDF s in the snapshots which might be an earlier draft

s in the snapshots which might be an earlier draft Google searches for queries like “ecash-pdf” and variants (sometimes adding in “Satoshi Nakamoto” since he was using that nick at the time even if he had not settled on “Bitcoin” as a name) have turned up no mirrors or people discussing that version of the whitepaper who might have copies

a more targeted search on BitcoinTalk did not turn up any copies

the whitepaper was never checked into the original Subversion repository set up after the alpha code was released, so no revision history there either

I asked them and learned that early correspondents Wei Dai, Adam Back, and Gregory Maxwell do not have copies. (I also asked Hal Finney but did not expect a reply given his condition & did not receive one before he passed away 2014-08-28.)

If anyone has a copy of it or a tip as to where it might be or who might have it stashed away, please contact me. It would likely shed some further insight on the development of Bitcoin and how Satoshi had his key insight of proof-of-work.

A request on the original “cryptography” mailing list yielded a SHA-256 hash of a draft paper earlier than the current bitcoin.org -hosted version, which then turned up a matching bitcoin.pdf (rehosted locally). Is this the earliest draft of the paper, the one Satoshi sent to Wei Dai? No: