Who Is Hal Finney? PGP Developer and First Bitcoin Recipient

Hal Finney was a cypherpunk and early PGP developer who received the first bitcoin transaction, 10 BTC in block 170, after 170 blocks of mining rewards alone. He built the RPOW digital-cash server in 2004, ran Bitcoin's software in its first days in January 2009 and died of ALS in August 2014.

Counted block by block, the chain shows why his payment is the first. Blocks 0 to 169 each hold exactly one transaction, the reward that paid their miner. Block 170, whose timestamp reads 12 January 2009, is the first block with a second one. It spent block 9's 50 BTC reward, paid 10 BTC to a new key and sent the other 40 BTC back to block 9's own key.

Hal Finney at a Glance

Who Is Hal Finney?

Hal Finney was a software engineer and an early cypherpunk, a member of the early-1990s mailing-list group that pushed encryption as a shield for personal privacy. His work ran from anonymous email to digital cash long before Satoshi Nakamoto published the Bitcoin whitepaper in late 2008.

Finney was also there at Bitcoin's start. His March 2013 essay Bitcoin and me says he grabbed the first release right away. "I think I was the first person besides Satoshi to run bitcoin," he wrote, and days later Satoshi sent him ten coins as a test.

Finney had already built on the computing puzzle that powers Bitcoin's mining. In 2004 he launched RPOW, a server that turned a hashcash proof of work into a token people could pass along, four years before Satoshi's design solved the same problem without a trusted server.

What Was Hal Finney's Career Before Bitcoin?

Finney got his start in cryptography on an early version of PGP, the email encryption program, working closely with its creator Phil Zimmermann. He wrote that he was one of the first hires when Zimmermann started PGP Corporation and that he kept working on PGP until he retired in early 2011. Wired wrote in August 2014 that he had been "the number-two developer" on PGP in the early 1990s.

He also ran anonymous remailers, servers that forward an email without the sender's address so nobody can tell who wrote it. In "Bitcoin and me" he put his own claim plainly. "I ran the first cryptographically based anonymous remailer," he wrote. His November 1992 essay Why Remailers I described the cypherpunks' work as "dedicated to this goal of making Big Brother obsolete."

In August 2004 he introduced RPOW, short for reusable proofs of work, on the cypherpunks mailing list as "my new hashcash-based server" and invited members to try it. A user handed in a hashcash token, which costs computing time to make, and got back a signed token that could change hands again and again.

Hal Finney's RPOW server ran on an IBM 4758 secure coprocessor, so any user could check that it issued tokens only against work of equal value. He later called it "an attempt to create my own proof of work based currency."

What Was the First Bitcoin Transaction?

The first bitcoin transaction was the 10 BTC test payment Satoshi Nakamoto sent Hal Finney, confirmed in block 170 in January 2009.

Every block before it holds a single transaction, the mining reward that created its coins, so blocks 0 to 169 moved no bitcoin from one key to another. Block 170's payment spent the 50 BTC reward of block 9, mined three days earlier by the blocks' timestamps, and split it in two.

It paid 10 BTC to a Bitcoin public key that had never appeared on the chain before. The other 40 BTC went back to the key that had received block 9's reward, and the payment carried no fee.

"I was the recipient of the first bitcoin transaction, when Satoshi sent ten coins to me as a test," Finney wrote in 2013. The chain itself carries no names, so his own account is what ties that key to him.

The 40 BTC of change didn't wait long. About two and a half hours later by the timestamps, block 181 spent it and sent another 10 BTC to a second key the chain doesn't name, keeping 30 BTC on block 9's key.

Rewards ran at 50 BTC a block in 2009, an amount Satoshi's release note said would be "cut in half every 4 years," and Phemex Academy follows that schedule to the end in how many bitcoins are left to mine.

Method: Every count above comes from the Bitcoin chain, read block by block for heights 0 to 170 through the public APIs of mempool.space and Blockstream's Esplora explorer, which return identical figures. They cover block 170's inputs and outputs and where each was later spent.

What Happened to the 10 BTC Satoshi Sent Hal Finney?

The 10 BTC stayed put for 673.7 days and then moved once, whole, in block 92,240 in November 2010. That spend had one input and one output, carried no fee and sent all 10 BTC to a single standard address.

The timing fits his own account of late 2010. Finney wrote that he heard about Bitcoin again that year and dusted off his old wallet, and that as the price rose he "transferred the coins into an offline wallet."

The chain can't confirm that the address in block 92,240 was that wallet, and nothing after that block links those coins to him.

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Did Hal Finney Know Satoshi Nakamoto?

Yes, Hal Finney knew Satoshi Nakamoto through email, and the written record starts on the cryptography mailing list. Finney answered the whitepaper there in November 2008 with "Bitcoin seems to be a very promising idea," though he admitted he was "having trouble fully understanding the system."

When Satoshi announced the first release in January 2009, Finney replied with "Congratulations to Satoshi on this first alpha release" and said he was looking forward to trying it out. He then "carried on an email conversation with Satoshi over the next few days, mostly me reporting bugs and him fixing them," as he wrote in 2013.

In the same January email, Finney ran "an amusing thought experiment" on what a coin could be worth. He reasoned that if Bitcoin became the world's dominant payment system, each of 20 million coins would carry a value of about $10 million. He framed it as a bet on long odds and asked if those odds were "really 100 million to one against."

Finney's impression at the time was of "a young man of Japanese ancestry who was very smart and sincere."

Why Is Hal Finney Not Satoshi?

Hal Finney denied being Satoshi, and one case on his side is a 10-mile race he ran in April 2009 while Satoshi was sending bitcoin.

The theory had a real basis. In March 2014 Forbes reporter Andy Greenberg sent a sample of Finney's writing to the writing-analysis firm Juola & Associates. Greenberg reported that Finney was "the best Nakamoto candidate whose writing the firm had ever analyzed."

"I'm flattered but I deny categorically these allegations," Finney wrote back, adding that his coding style was "completely different from Satoshi's."

Greenberg then saw the January 2009 emails between Finney and Satoshi, about fifteen of them, and concluded that Finney was telling the truth. The firm later found that Satoshi's side of those emails matched the whitepaper's style more closely than Finney's own writing did.

Jameson Lopp's October 2023 post "Hal Finney Was Not Satoshi Nakamoto" added a timing test. It set Finney's race on 18 April 2009, which lasted an hour and 18 minutes, against a Satoshi payment to developer Mike Hearn. That payment confirmed in block 11,408, whose timestamp falls about 55 minutes into the race, and Lopp dated a Satoshi email to Hearn two minutes before Finney finished.

A newer theory points away from Finney altogether. Phemex's write-up on Adam Back and the New York Times investigation covers the April 2026 story that named hashcash creator Adam Back as the most likely Satoshi, a claim Back denied.

What Is a Finney Attack?

A Finney attack is a double spend against a merchant who hands over goods before a payment confirms, and Finney described it in a forum reply in February 2011.

The attacker mines a block that includes a transfer between two of his own addresses and keeps that block to himself. He then pays the merchant from the first address, waits for the goods and broadcasts the hidden block, whose transfer spends the same coins first. In Finney's words, the attacker "runs down to your store and makes a payment to your address C with his address A."

It works only against a payment accepted before it lands in a block, because the attacker needs a block he has already mined and kept back. That's why merchants and exchanges wait for confirmations on larger sums.

Frequently Asked Questions

Did Hal Finney deny being Satoshi Nakamoto?

Yes. In March 2014 he told a Forbes reporter in writing that he denied "categorically" being Satoshi. The reporter later saw Finney's January 2009 emails with Satoshi and concluded he was telling the truth.

How did Hal Finney contribute to Bitcoin?

He reviewed the design on the cryptography mailing list in November 2008, ran the software from its January 2009 release and reported bugs that Satoshi fixed. He received the first transaction in block 170 and in February 2011 described the double spend later named after him.

What was Hal Finney's RPOW?

RPOW, short for reusable proofs of work, was a digital-cash server Finney launched in August 2004. It took a hashcash proof of work and issued a signed token that could pass from person to person, about four years before the Bitcoin whitepaper appeared.

Which block holds Hal Finney's first bitcoin transaction?

Block 170, whose timestamp reads 12 January 2009, holds it. It is the first block on the Bitcoin chain with more than one transaction, and it moved 10 BTC out of block 9's mining reward.

Bottom Line

One fact in Hal Finney's story is written into the chain itself. Out of 171 blocks, one holds a payment between two keys, and his 2013 essay puts his own name on the receiving end. Every Satoshi theory about him leans on writing style and coincidence, and none of them can move that census.

Disclaimer: This article is for informational purposes only and is not financial advice. Cryptocurrency trading involves substantial risk. Always do your own research before making investment decisions.