Private email — scalability questions

This email was sent during the pre-release code review period, approximately two months before Bitcoin’s public launch. Finney had been reviewing Satoshi’s code and draft paper, and wrote to ask fundamental scalability questions:

How large do you envision it becoming? Tens of nodes? Thousands? Millions?

He also asked:

And for clients, do you think this could scale to be usable for close to 100% of the world’s financial transactions?

These questions demonstrate that Finney — a veteran cryptographer who had worked on PGP and created the first reusable proof-of-work system (RPOW) — was thinking seriously about Bitcoin’s potential from the very beginning. While most recipients of the whitepaper on the Cryptography mailing list were skeptical, Finney was one of the few who engaged deeply with the technical details.

This email was published by CoinDesk on November 26, 2020, based on files from Hal Finney’s personal computer that his widow Fran Finney provided to journalist Nathaniel Popper (author of Digital Gold) in March 2014.

[Source: Published by CoinDesk, November 26, 2020. Original files provided by Fran Finney to Nathaniel Popper in March 2014, subsequently shared with CoinDesk journalist Michael Kapilkov.]

Sent from satoshi@vistomail.com on Thursday, January 8, 2009 at 20:54:55 PST — just hours after the public announcement on the Cryptography mailing list — Satoshi personally notified Hal Finney of the Bitcoin release:

Thought you’d like to know, the Bitcoin v0.1 release with EXE and full sourcecode is up on Sourceforge: http://downloads.sourceforge.net/bitcoin/bitcoin-0.1.0.rar

www.bitcoin.org has release notes and screenshots.

Satoshi

This brief personal email shows that Satoshi valued Finney’s involvement enough to send a private notification in addition to the public announcement. Finney responded by downloading the software and posting his famous “Running bitcoin” tweet on January 11, 2009. The next day, January 12, Satoshi sent Finney 10 BTC in block 170 — the first known person-to-person Bitcoin transaction.

Hal Finney later recalled in his “Bitcoin and me” post (March 2013): “I carried on an email conversation with Satoshi over the next few days, mostly me reporting bugs and him fixing them.”

[Source: Published by CoinDesk, November 26, 2020. Original files from Hal Finney’s personal computer, provided by Fran Finney to Nathaniel Popper in March 2014.]

In this email, sent in the earliest days of the Bitcoin network, Satoshi disclosed a technical constraint:

Unfortunately, I can’t receive incoming connections from where I am, which has made things more difficult.

This admission reveals that Satoshi was operating behind a firewall or NAT that blocked incoming TCP connections on port 8333, making his own node dependent on outgoing connections to other peers. This would have complicated debugging and testing the network in its infancy when there were only a handful of nodes.

The email headers contained a timezone of UTC+8, which triggered speculation about Satoshi’s location. However, Chain Bulletin journalist Doncho Karaivanov demonstrated that the UTC+8 timestamp originated from AnonymousSpeech.com’s email relay server (based in Tokyo since 1996, using Asia/Hong_Kong timezone), not from Satoshi’s local machine.

This email is part of the private correspondence recovered from Hal Finney’s personal computer files. Finney described the broader exchange in his “Bitcoin and me” post: “I carried on an email conversation with Satoshi over the next few days, mostly me reporting bugs and him fixing them.” Only three of these private emails have been published; the remainder presumably exist in the files Fran Finney provided to journalist Nathaniel Popper in March 2014.

[Source: Published by CoinDesk, November 26, 2020. There is a date discrepancy across sources — this email may have been sent on January 10 or January 12, 2009.]