Some bitcoin enthusiasts have used their cryptocurrency to travel around the world. Others have spent it on a trip to space. But the very earliest user of bitcoin (after its inventor Satoshi Nakamoto himself) has now spent his crypto coins on the most ambitious mission yet: to visit the future.

Hal Finney, the renowned cryptographer, coder, and bitcoin pioneer, died Thursday morning at the age of 58 after five years battling ALS. He will be remembered for a remarkable career that included working as the number-two developer on the groundbreaking encryption software PGP in the early 1990s, creating one of the first "remailers" that presaged the anonymity software Tor, and—more than a decade later—becoming one of the first programmers to work on bitcoin's open source code; in 2009, he received the very first bitcoin transaction from Satoshi Nakamoto.1

Now Finney has become an early adopter of a far more science fictional technology: human cryopreservation, the process of freezing human bodies so that they can be revived decades or even centuries later.

Just after his legal death was declared Thursday at 9 a.m., Finney's body was transported from a Scottsdale, Arizona hospital to a nearby facility of the cryonics firm known as the Alcor Life Extension Foundation. As of Thursday night, Finney's blood and other fluids were being removed from his body and slowly replaced with a collection of chemicals that Alcor calls M-22, which the company says are designed to be as minimally toxic as possible to his tissues while preventing the formation of ice crystals that would result from freezing and destroy his cell membranes.2

Over the next few days, the temperature of his body will be slowly lowered to -320 degrees Fahrenheit. Eventually, it will be stored in an aluminum pod inside a 10-foot tall tank filled with 450 liters of liquid nitrogen designed to keep him in that state of near-complete suspended animation. "That's where he’ll remain until such time as we have technologies to repair the problems he had such as ALS and the aging process," says Max More, Alcor's director and Finney's friend of many years. "And then we can bring Hal back happy and whole again."

No human, to be clear, has ever been revived from a state of cryonic freezing. Many scientists consider the idea impossible. But Finney's wife Fran says that doubters never stopped her husband from exploring a technology that intrigued him.

"Hal respects other people’s beliefs, and he doesn’t like to argue. But it doesn’t matter to him what other people believe," says Fran, who alternatingly spoke about her husband in the present and past tense. "He has enough confidence in how he figures things out for himself. He's always believed he could find the truth, and he doesn’t need to convince anyone."

In fact, Finney and his wife both decided to have their bodies cryonically frozen more than 20 years ago. At the time, Finney, like Alcor's president More, was an active member of the Extropians, a movement of technologists and futurists focused on transhumanism and life extension. "He’s always been optimistic about the future," says Fran. "Every new advance, he embraced it, every new technology. Hal relished life, and he made the most of everything."

Finney was also an avowed libertarian and well-known figure within the cypherpunks, another early '90s, mailing-list-centered group focused on empowering individuals with encryption, preserving privacy, and foiling surveillance. Finney created the first so-called "cypherpunk remailer," a piece of software that would receive encrypted email and bounce messages to their destinations to prevent anyone from identifying the sender. He also became the first coder to work with Phil Zimmermann on Pretty Good Privacy or PGP, the first freely available strong crypto tool, and designed the software's "web-of-trust" model of verifying PGP users' identities.

That same forward-looking spirit led Finney to embrace bitcoin before practically anyone other than its creator thought it might be a viable system, let alone a multi-billion dollar economy. Finney spotted Satoshi Nakamoto's bitcoin whitepaper on a cryptography mailing list in 2008 and immediately began exchanging emails with him, eventually helping to debug its code, perform its first test transactions, and mine a substantial hoard of the cryptocurrency. "I've noticed that cryptographic graybeards...tend to get cynical. I was more idealistic; I have always loved crypto, the mystery and the paradox of it," Finney wrote on the BitcoinTalk forum last year. "When Satoshi announced Bitcoin on the cryptography mailing list, he got a skeptical reception at best...I was more positive."

Finney's positivity extended to his personal interactions, too. Colleagues from as early as college say he was as kind and generous as he was brilliant. "Hal is a rare genius who never had to trade his emotional intelligence to get his intellectual gifts,” Zimmermann told me in an email when I was writing a profile of Finney last March. “He is a fine human being, an inspiration for his attitude toward life. I wish I could be like him."

Even Finney's ALS diagnosis in 2009 didn't slow his technological experimentation. As paralysis set in, he continued to contribute to bitcoin discussions and write code using software that translated his eye movements into text. He even created software that allowed him to use his eyes to adjust his own mechanized wheelchair's position.

When I visited Finney in his Santa Barbara home earlier this year, his eye control was beginning to fail, too, and he was mostly reduced to delivering yes-and-no answers to my questions based on eyebrow movements. Even then, he was extraordinarily kind—he spent the first 10 minutes of our conversation composing a sentence on his computer telling me not to feel bad that I had gotten caught in traffic and arrived 15 minutes late.

Finney never quite got rich from his early bitcoin involvement, according to Fran. Much of their savings went toward his health care as his condition deteriorated. They traded the majority of his bitcoins for dollars long before the currency's spike in value late last year.

After my story on Finney's life and work, bitcoiners donated 25 bitcoins to Finney and his family, a sum that's worth close to $12,500 today. Initially, Fran Finney tells me, the family intended to spend that money to buy Finney a new computer interface that would use an electromyographic (EMG) switch to read electric signals from surface muscle, allowing him to better control his voice and writing software. But the interface was incompatible with the few muscles Finney still controlled, leaving him locked in a body that increasingly prevented him from communicating at all.

So instead, the bitcoin donations will now go toward Finney's cryonic procedures, along with a life insurance policy the Finneys have maintained for years to prepare for Alcor's substantial fee. "Once we realized that Hal wasn’t going to be able to use the EMG switch, this was our next choice," says Fran. "The bitcoins will cover a large fraction of the cost."

Already, Fran says, the idea that her husband has been preserved in some sense comforts her. "It isn’t going to take away the fact that he’s not here now," she says. "But it’s been very calming and reassuring for me to know that he might come back."

Around the time of his diagnosis, Finney said he found that his cryonics plan gave him some comfort, too. "It was actually extremely reassuring as the reality of the diagnosis sunk in," he wrote in 2009. "I was surprised, because I've always considered cryonics a long shot. But it turns out that in this kind of situation, it helps tremendously to have reasons for hope, and cryonics provides another avenue for a possibly favorable outcome."

Fran Finney says that her husband had no illusions about the certainty of his resurrection. But until his final moments, he put his faith in the progress of technology. "He never said to me, 'I will come back.' But he told me, 'I hope to be back,'" Fran says. "Hal liked the present. But he looked towards the future. He wanted to be there. And this is his way to get there."

1Correction 8/29/2014: An earlier version of this story stated that Finney received the first bitcoin transaction from Satoshi Nakamoto in 2008. In fact it occurred in January, 2009.

2Correction 9/2/2014: An earlier version of the story stated that Finney was flown to the Alcor facility after his legal death. In fact he was transported from a nearby hospital after flying to Arizona before his death.