Active 2008–2011; identity unknown · Unknown (pseudonymous)
Satoshi Nakamoto
Publishing the Bitcoin white paper and launching the Bitcoin network
Satoshi Nakamoto is the name used by the person or people who published the Bitcoin white paper, "Bitcoin: A Peer-to-Peer Electronic Cash System," in October 2008, and who released the first Bitcoin software and mined the genesis block in January 2009.
Nakamoto corresponded with early cryptographers and cypherpunks on the Cryptography Mailing List and the P2P Foundation forum, wrote much of the original reference client, and continued to contribute code and respond to other developers through 2010.
In mid-2010, Nakamoto handed control of the source code repository and network alert key to developer Gavin Andresen and other early contributors. Public communication from the Nakamoto account tapered off in December 2010 and stopped entirely by 2011. The identity behind the name has never been confirmed.
- Authored the Bitcoin white paper (October 2008)
- Mined the Bitcoin genesis block (January 2009)
- Wrote the original Bitcoin reference client
1956–2014 · California, United States
Hal Finney
Receiving the first Bitcoin transaction; early cypherpunk and cryptographer
Harold "Hal" Finney was a computer scientist and one of the earliest members of the cypherpunk movement, known for his work on PGP encryption and for creating RPOW (Reusable Proof of Work), a precursor system to Bitcoin.
In January 2009, Finney downloaded the first Bitcoin software release and received the first Bitcoin transaction on record, sent to him by Satoshi Nakamoto. He corresponded with Nakamoto in the network's earliest days and contributed to early discussion of its design.
Finney was diagnosed with amyotrophic lateral sclerosis (ALS) in 2009. He continued to write about and contribute to Bitcoin as his health allowed in the years that followed, and died in 2014.
- Created RPOW (Reusable Proof of Work), 2004
- Received the first Bitcoin transaction, January 2009
- Early contributor to Bitcoin's design discussion
Active from the 1990s · United States
Nick Szabo
Proposing "bit gold" and coining the term "smart contracts"
Nick Szabo is a computer scientist and legal scholar who, in the 1990s, coined the term "smart contracts" to describe self-executing digital agreements, and in 1998 proposed "bit gold," a design for a decentralized digital currency using proof-of-work.
Bit gold was never implemented, but it anticipated several ideas later used in Bitcoin, and Szabo is widely regarded by Bitcoin researchers and historians as one of the most direct intellectual precursors to Nakamoto's design.
- Coined the term "smart contracts", 1990s
- Proposed "bit gold", 1998
Active from the 1990s · United States
Wei Dai
Proposing "b-money", cited directly in the Bitcoin white paper
Wei Dai is a computer engineer who, in 1998, published a proposal called "b-money" describing an anonymous, distributed electronic cash system. Bitcoin's white paper cites b-money as a reference.
Dai is also the author of Crypto++, a widely used open-source C++ cryptographic library. The smallest denomination of ether on the Ethereum network, the "wei," is named after him.
- Proposed "b-money", 1998
- Author of the Crypto++ cryptographic library
Born 1970 · United Kingdom
Adam Back
Inventing Hashcash, the proof-of-work system Bitcoin mining is built on
Adam Back is a British cryptographer who created Hashcash in 1997, a proof-of-work system originally designed to deter email spam. The Bitcoin white paper cites Hashcash directly, and Bitcoin's mining process is built on the same proof-of-work principle.
Back corresponded with Satoshi Nakamoto prior to Bitcoin's public release. In 2014 he co-founded Blockstream, a company that builds Bitcoin infrastructure, and has remained an active figure in Bitcoin development and commentary since.
- Invented Hashcash, 1997
- Co-founded Blockstream, 2014
Born 1966 · United States
Gavin Andresen
Lead maintainer of Bitcoin Core after Satoshi Nakamoto stepped back
Gavin Andresen is a software developer who became an active Bitcoin contributor in 2010. That year, Satoshi Nakamoto handed him the network alert key and access to the source code repository, and Andresen became the lead maintainer of the Bitcoin reference client.
He went on to found the Bitcoin Faucet, an early tool for distributing small amounts of bitcoin to newcomers, and later served as chief scientist at the Bitcoin Foundation, continuing to guide the project's development in its early years.
- Lead maintainer of Bitcoin Core, 2010 onward
- Founded the Bitcoin Faucet
- Chief scientist, Bitcoin Foundation
Active from 2011 · Belgium
Pieter Wuille
Core Bitcoin developer behind Segregated Witness and key infrastructure
Pieter Wuille is a computer scientist who joined Bitcoin Core development in 2011 and has been one of its most consistent contributors since. He co-authored Segregated Witness (SegWit), a major protocol upgrade activated in 2017, and BIP32, the standard behind hierarchical deterministic wallets.
Wuille also authored libsecp256k1, the cryptographic library Bitcoin Core uses for its elliptic-curve operations, and is a co-founder of Blockstream.
- Co-authored Segregated Witness (SegWit)
- Authored BIP32 (hierarchical deterministic wallets)
- Authored libsecp256k1
- Co-founded Blockstream
Active from 2009 · United States
Laszlo Hanyecz
"Bitcoin Pizza Day" — the first recorded real-world Bitcoin purchase
Laszlo Hanyecz is a programmer and one of Bitcoin's earliest miners, known for contributing early GPU-mining code that significantly increased the network's mining efficiency.
On May 22, 2010, Hanyecz posted on the Bitcointalk forum offering 10,000 bitcoin for two pizzas. Another user arranged the delivery, completing what is generally regarded as the first real-world commercial transaction using Bitcoin. The date is now commemorated annually as "Bitcoin Pizza Day."
- Early GPU-mining code contributions
- Completed the first recorded real-world Bitcoin transaction, May 2010
Active from 2009 · Newport, Wales, United Kingdom
James Howells
Accidentally discarding a hard drive holding an early Bitcoin fortune
James Howells is a Welsh IT worker who mined bitcoin in 2009 and 2010 on a personal laptop. In 2013, during a clear-out, the hard drive containing his wallet's private keys was mistakenly thrown away and ended up buried in a landfill site in Newport, Wales.
Howells has since made repeated attempts to gain permission to search the landfill, including a lawsuit against Newport City Council seeking access to excavate the site, which was unsuccessful. As of this writing, the hard drive has not been recovered.
Born 1942 · California, United States
Dorian Nakamoto
Wrongly identified by the press as the creator of Bitcoin
Dorian Prentice Satoshi Nakamoto is a Japanese-American engineer who, in March 2014, was identified by a Newsweek cover story as the creator of Bitcoin, based on circumstantial details including his birth name.
Nakamoto denied any connection to Bitcoin's creation or design. The Bitcoin-founder account on the P2P Foundation forum, dormant for years, briefly resurfaced to post "I am not Dorian Nakamoto," and other early Bitcoin contributors also said they did not believe he was involved. He experienced a period of intense media attention as a result of the story.