Satoshi ↔ Laszlo Hanyecz Correspondence
Laszlo Hanyecz, a software developer from Jacksonville, Florida, became one of Bitcoin’s most important early contributors. He registered on the Bitcointalk forum shortly before creating the first macOS client for Bitcoin Core on April 19, 2010.
Hanyecz and Satoshi Nakamoto exchanged hundreds of emails during Bitcoin’s early days, making their correspondence one of the most extensive private communications Satoshi had with any individual. Hanyecz later described their exchanges as “mostly weird,” noting that Satoshi would not respond to emails for weeks and then answer everything at once, often on Fridays.
Satoshi frequently emailed Hanyecz with development requests. As Hanyecz later recalled in interviews, Satoshi would send messages like: “Hey, can you fix this bug?” or “Hey, the west side’s down,” or “We have these bugs — we need to fix this.”
Hanyecz described Satoshi’s communication style as “paranoid,” “bossy,” and “a little bit weird,” though he continued to contribute significant development work to the project, including the macOS port and early experimentation with GPU mining.
Source: Based on interviews with Laszlo Hanyecz published by Bitcoin Magazine, CoinDesk, and other outlets. The full private email correspondence between Hanyecz and Satoshi has not been publicly released, though Hanyecz has shared numerous quotes and details in interviews.
After Laszlo Hanyecz announced his GPU mining discovery on the Bitcointalk forum on May 10, 2010, Satoshi Nakamoto emailed him privately expressing concern. Hanyecz had been the first person to successfully use a GPU (graphics processing unit) to mine Bitcoin, achieving dramatically higher hash rates than CPU mining allowed.
Satoshi wrote to Hanyecz:
A big attraction to new users is that anyone with a computer can generate some free coins. GPUs would prematurely limit the incentive to only those with high-end GPU hardware. It’s inevitable that GPU compute clusters will eventually hog all the generated coins, but I don’t want to hasten that day.
In a separate message, Satoshi was more direct:
Hey, can you go slow with this? […] Look, I don’t care if people hoard the Bitcoin, I don’t care if the wealth is concentrated. But right now, the big attraction is that anybody can download Bitcoin and start mining with their laptop.
Hanyecz later recalled feeling guilty about the impact of his discovery. In a 2019 interview, he said: “I stopped advertising [GPU mining] after that. I was like, ‘Man, I feel like I crapped up your project. Sorry, dude.’ He was concerned that some people might be discouraged because they can’t mine a block with a CPU.”
This exchange is particularly revealing because Satoshi was not opposed to GPU mining on ideological grounds — he explicitly stated he did not care about wealth concentration. His concern was purely strategic: premature GPU adoption would harm early network growth by removing the incentive for ordinary users to participate.
Source: Quotes from Satoshi’s emails as shared by Laszlo Hanyecz in multiple interviews, including with CoinDesk (2025), Bitcoin Magazine, and Cointelegraph. The full private correspondence has not been publicly released.
In a remarkable exchange that occurred after Laszlo Hanyecz shared his GPU miner code with Satoshi, Satoshi reciprocated by sharing his own independently developed GPU mining code. This revelation showed that Satoshi had been working on GPU mining before Hanyecz’s public announcement — not to mine coins, but as a contingency plan to defend the network against potential 51% attacks.
As Hanyecz later recounted:
And he actually shared with me his version of it. So even though it wasn’t in Bitcoin, he did have GPU mining code and he said he was just keeping it ready in case he had to defend the network with it.
Satoshi had developed several versions of the GPU mining algorithm but deliberately chose not to include it in the public Bitcoin software. His strategic reasoning was twofold: he wanted to keep GPU mining capability as a defensive weapon against potential attackers, and he did not want to prematurely increase network difficulty, which would have discouraged ordinary CPU miners from participating.
Hanyecz noted that his own GPU code actually performed better than Satoshi’s version, but that Satoshi had intentionally avoided optimizing it:
And I got the feeling, that part of it was that he didn’t want to prematurely optimize it because he didn’t want to run up the difficulty on the network.
This exchange reveals a fascinating aspect of Satoshi’s strategic thinking: he was simultaneously discouraging public GPU mining to protect accessibility while privately maintaining GPU mining capability as insurance against adversarial attacks. It demonstrates that Satoshi had thought deeply about potential attack vectors and had prepared defensive measures well in advance.
Source: Based on Laszlo Hanyecz’s public statements in interviews with Cointelegraph and other outlets. The full private email correspondence has not been publicly released, but Hanyecz has shared these details in multiple interviews.