Hacker Fiction Net

Review of Johnny Mnemonic (1981, 1995)

A 1981 short story by William Gibson and a 1995 movie directed by Robert Longo and written by Gibson.

Spoiler Alert. Yeah, there are spoilers below.

Hacker Rating

Hacker Realism: ⭐️ ⭐️

Hacker Importance for the Plot: ⭐️ ⭐️ ⭐️ ⭐️

Hacks: ⭐️ ⭐️ ⭐️

Rent or buy on Amazon, Apple, or Google.

The Short Story

The short story is just 22 pages in paperback and features Gibson’s typical dense language and the cyberpunk world which later provided the backdrop for the Sprawl trilogy Neuromancer, Count Zero, and Mona Lisa Overdrive. I got it in print as a part of the 1986 short story collection Burning Chrome.

Johnny Mnemonic in its original form is a great piece with more dirty cyberpunk than the movie, but it doesn’t feature as much hacking so I’ll focus on the movie here and mention when book and movie touch each other.

Opening page of the printed 'Johnny Mnemonic' by William Gibson, from a vintage paperback copy of the short story collection 'Burning Chrome.'

The Movie Premise(s)

The film's prologue lets us learn that in this future (2021!) people all over the world are suffering from Nerve Attenuation Syndrome, or NAS. It's a fatal epidemic and its cause and cure are unknown. We are also told that corporations rule, opposed only by LoTeks – a resistance movement from the streets who are hackers “in the info-wars.” The corporations defend themselves by hiring Yakuza – a powerful crime syndicate.

Then we meet Johnny Mnemonic (Keanu Reeves) who is a data courier – a person who smuggles data in brain implants. He has a successful career behind him and is on his last assignment, headed off to a hotel in Beijing where customers will provide him the data to transfer to Newark, NJ.

Storage Capacity of the Brain

Heading up to his customers, Johnny connects a small device to his brain. The device speaks to him, saying “Present capacity 80 gigabyte. Doubler loading. Your storage capacity is now 160 gigabyte. Warning, do not exceed capacity.” We later learn that Johnny has had to discard his childhood memories to free up brain space and he has even forgotten his family name.

In today’s world, 80 gigabyte is not that much. It’s roughly the size of three movies in 4k resolution and the brain is thought to have far larger storage capacity than that, in the order of a couple of petabytes, each of which is a million gigabytes.

Still, data storage is different than memories. Data needs to remain intact down to the very last bit whereas human memories are fuzzy, or lossy if you will. I would assume that storing data in Johnny’s brain uses a lot of redundancy to cover up for any bit rot during the hours it takes for him to get to his destination so 80 gigs might be reasonable.

The Data in Johnny’s Head

His customers want Johnny to carry 320 gigabyte of data which will far exceed his already doubled capacity of 160. He fishes out all kinds of equipment and a downward counter for the data transfer to his brain. He tells the customers that when the counter approaches zero, they should take three shots of what’s on the TV in the hotel room.

“They’ll meld with the data and I won’t know what they are. That’s the download code. You get a hardcopy. You fax one copy to your connection on the other side. When I get there, we feed in the code and download. Understand?”

Since these frames are to be taken toward the end of the data transfer to his brain, they can’t be used as a cryptographic key straight up. My reading of this is that Johnny’s equipment generates a crypto key at the start of the transfer, say KeyA, encrypts the data with KeyA as it is transferred to his brain, and then encrypts KeyA with a second key, KeyB, generated from the three frames from the TV. That way, only someone with access to the TV frames can generate KeyB, with it decrypt KeyA, and with KeyA decrypt his brain’s content. That’s similar to the layering where you protect a set of passwords with a main password.

But it doesn’t explain why the data cannot even be downloaded from his brain without the key. Supposedly his implant doesn’t even let go of the data without the right key. That would become a big problem for Johnny if the key was lost, mainly because of the excess data he’s carrying. The longer he keeps that amount of data stored, the higher the risk of his brain malfunctioning, killing him and corrupting the data.

The transfer of 320 gigabyte takes 55 seconds in the movie and it’s done over cable. That’s a transfer speed of 47 gigabit per second which is right up there at modern Ethernet speeds in datacenters.

Tracing the Data Transfer

Problems arise as crime syndicate Yakuza bursts into the hotel room, kills Johnny’s customers, and has him fleeing. Yakuza want what’s in his head, without his body attached. He manages to snatch one of the access code TV frames but needs all three to offload his digital cargo. Will he be able to get the data out of his brain safely and why is Yakuza so desperate to get it?

Johnny gets access to a computer, enters cyberspace, and hacks his way into the phone records of the Beijing hotel from where the TV frames were faxed. The fax destination was a copyshop in Newark but the only data he can retrieve says “Hold for Dr. Allcome. WILL CALL.”

The hack is so abstract that there’s not much to go on. However, the goal and the steps with the phone records and where the data is sent feels realistic. That’s exactly the kind of metadata carriers collect and store, and what an attacker would be able to learn. Let's just gloss over the fact that they’re sending super sensitive data over fax in 2021.

Cyberspace is shown as a 3D graphics space with highways and movement in all directions. People nowadays are so used to Internet access through their smartphones that you don’t need to represent it as a world. But it makes for spectacular visuals.

The Virus

While Johnny is hacking the fax transfer, Yakuza lock onto his network connection and physically locate him. The Yakuza leader issues an order: “Initiate the virus.”

Johnny, who doesn’t know there’s a virus coming for him, calls his friend Strike on the network. Strike says Johnny’s a target. That reads to me like Strike seeing there are ongoing attempts at hacking Johnny’s terminal but it could also be something purely virtual – an attack on Johnny’s avatar.

Johnny: I need to know what I’m holding, Strike. What’s the Yakuza after? Who’s Dr. Allcome?

Strike: All I know is you’ve got a head full of PharmaKom data and they hired the Yakuza to get it out.

Johnny: PharmaKom?

Strike: Shit, they put a virus on us!

PharmaKom is a powerful medical corporation. It’s a bit unclear what it means to get a virus in cyberspace but they at least lose their connection. Yakuza arrive in three cars. Johnny barely makes it out.

The Virtual Human Anna Kalmann

There’s a cutaway scene where boss Takahashi (Takeshi Kitano) from the PharmaKom corporation learns that Anna Kalmann (Barbara Sukowa), founder of PharmaKom and his advisor, only exists in virtual form. She’s been “imprinted to PharmaKom’s natural net installation in Zurich prior to onset of morbidity,” her “neural net persona has Swiss citizenship under the artificial intelligence laws of 2006,” and “she advises the current board from this state of being.”

While fascinating, the movie doesn’t really explore this state of existence. Anna shows up a few times and is pulling strings but remains illusive. Other stories such as Ready Player One and The Matrix go much deeper into virtual life.

Side note: Takahashi refers to Anna Kalmann as “a ghost in the machine.” That could be a reference to the sci-fi movie Ghost In the Machine from 1993 or a reference to Ghost in the Shell which is a manga story that was released as a movie the same year as Johnny Mnemonic.

Nerve Attenuation Syndrome, NAS

Johnny gets help from Jane (Dina Meyer) who saved his life early in the movie and wants him to survive so he can pay her. She’s named Molly Millions in the short story (a much better name) and kicks ass in both.

Jane takes Johnny to an underground physician and we learn that PharmaKom is charging $2k for treatment of NAS. $2k in 1995 equals $3.5k today and is still a lot of money in parts of the world but it’s kind of telling that it is supposed to sound outrageously expensive for healthcare in the US.

The physician tells Johnny that Dr. Allcome is used as in “Dr. all come to ward 7” – code speak used to not spook patients. But in this case, the fax for Dr. Allcome was intended for the underground healthcare organization the physician is working for where they treat people who have NAS and can’t afford PharmaKom’s $2k. They need what’s in Johnny’s head.

“You’re carrying the cure for NAS. PharmaKom’s complete R&D on their cure for NAS. Plus the records of the field trials to prove that it works.”

NAS is said in the movie to be caused by information overload from using the Internet. The closest I can come to think of is the ongoing research into how social networks affect us, with worrying scientific conclusions like this one in the American Journal of Health Behavior:

Participants were characterized as "Wired," "Connected," "Diffuse Dabblers," "Concentrated Dabblers," and "Unplugged." Membership in 2 clusters - "Wired" and "Connected" - increased the odds of elevated depression and anxiety symptoms.

Jones the Cyborg Dolphin

Jane also connects Johnny with the LoTeks – the rebellion opposed to corporate rule living in the outskirts of the city in slum-like conditions.

The LoTek’s mastermind code breaker is Jones – an electronically enhanced dolphin that used to be part of US military defense. “Jones is set up to sample software from enemy subs. Infrasound scan. Right through the hull.”

Jones tries to hack into Johnny’s brain and get the cure for NAS out safely with the one TV frame Johnny has. However, Yakuza shows up and starts shooting anti tank missiles at LoTek HQ which disrupts Jones’s hacking attempts.

With Jones, the author Gibson connects the movie with his old short story. In the book, Jones’s technology is called Squids – superconducting quantum interference detectors. “Used them in the war to find submarines, suss out enemy cyber systems.” It’s by far the story’s most imaginative part but neither short story nor movie makes much of it. The dolphin is key to the resolution but we don’t get to explore this fascinating technology.

Side note: Jones makes me think of the classic sonar pings in submarine movies like Das Boot. I have started researching sound travel in ocean water but that’s for my own fiction writing so you’ll have to wait.

The Final Hack

For the final scene and hack, Takahashi, Anna Kalmann, and the Yakuza all show up and it gets messy. Takahashi eventually gives Johnny the remaining two TV frames with his dying breath.

Johnny is told by LoTek leader J-Bone (Ice-T) that “the only way is to hack your own brain, then loop it through Jones.”

Johnny goes into cyberspace to try to hack his own brain but PharmaKom puts up a fight and “initiates” a virus. Johnny then creates a mirror image of himself in cyberspace to make the virus go for the copy. Jones arrives as a virtual dolphin and together they decipher the last TV frame, download PharmaKom’s data, and broadcast the cure for NAS to the world.

The short story contains a resolcing hack by Jones and does a better job of it with a visual reveal in text (I won’t spoil that particular part for you).

The high pace required for a climactic ending is a challenge for hacker fiction since hacking isn't fast. Unless you mean just executing an already packaged hack in which case it takes less than a second.

The mirror image hack sounds like what’s called a honeypot in cybersecurity, with which you lure the attacker to target a system that you don’t care about. The broadcast of the cure for NAS makes me remember the failed attempts at restricting export of strong cryptography in the 90s. The most famous hack against that restriction was printing the crypto source code on t-shirts and wearing them as you travelled – data courier style like Johnny Mnemonic!


A beautiful, intriguing word – mnemonic. The dictionary explains it as “a device such as a pattern of letters, ideas, or associations that assists in remembering something.” A mnemonic I learned in school was “I before E except after C” for spelling words like thief and receive. In the scope of Gibson’s story, I interpret mnemonic as a bridge between the plastic human mind and the rigid structure of computer data – the brain needs help storing and emitting exact information, and that help is some form of mnemonic.

Unsurprisingly, the premise of Johnny Mnemomic and the cyberspace/hacker pieces of it are still imaginative. Gibson is one of the masters of hacker fiction and has a great skill for creating stories of what could happen.

I had to review this movie this year since present time matches when the story takes place. Setting a specific date for your futuristic fiction has pros and cons. Audiences love envisioning something that might happen in their lifetime or just thinking of what’s possible in ten or fifty years. But the real world catches up faster than you think and all the things that progress differently risk becoming comical or confusing in the piece of fiction.

William Gibson talked about this science fiction challenge in a 2011 interview:

One of the funniest things about Neuromancer, which I wrote in 1984, is that there are no cell phones. If I were a 14-year-old reading it today, I’d be about two chapters in and think, “What happened to all the cell phones?” Becoming quaint so quickly in science fiction is unavoidable. Either we won’t see the technologies that are emerging ahead of us, or we won’t be able to see the uses that people will put them to, which are almost never what they were intended for.

The cyberpunk parts with LoTeks, slum, and violence are not very exciting to me even though I do love cyberpunk in general. It’s just not well executed. The movie’s hacking parts are highly visual and use keywords such as virus but the one hacking snippet in the short story is actually better than what the movie has to offer. What’s lacking here is any kind of clever reveal – something to make the viewer go “Aha” and get it. The short story has a little tiny bit of that in that Jones the dolphin actually finds a code which is connected to the character who chose it (no TV frames there).

I didn’t mention Dolph Lundgren in my review but he does play an over the top character called “The Preacher.” I’d say it’s the most colorful part of the movie. Fun fact: This was Lundgren’s last Hollywood appearance until The Expendables in 2010.

This text was originally published in the July 2021 issue of the Hacker Chronicles newsletter. Subscribe below!