The opening scene of Swordfish is the most complicated visual effect in Warner Brothers history. It was shot using Matrix-like effects (The Matrix (1999)) by Frantic Films of Winnipeg, Manitoba, Canada. The effect has so many composites in it that the producers and director of the film could not determine what was real and what was created by computer.
Rudolf Martin plays Axl Torvalds, a hacker of some renown in the film. The character is named after Linus Torvalds, a "hacker" in real life, who wrote Linux Kernel, the original code for the open source computer Operating System named after him, Linux. Axl and Linus are both Finnish.
When Gabriel is recruiting Stanley he mentions "Vernam encryption." In real life Gilbert Vernam worked at Bell labs in the early 1900s and patented a special cipher that was eventually proved to be "uncrackable."
When Stanley and Agent Roberts are reviewing their past dealings Roberts accuses Stanley of hacking into the US government's Carnivore system and Stanley claims he did it because the government was illegally spying on US citizens' emails. This plot line was likely considered a far-fetched notion to viewers of a movie that was released months before the 9-11 attacks and more than a year before real-life government spying of the kind described in the movie was exposed.
Unlike many Hollywood movies, the amount of the ammunition in firearms is depicted correctly. During the chase sequence, Gabriel fires a total of 89 shots from M249 Squad Automatic Weapon, which carries a 200 round box.
At one point during Stanley's attempt to hack into the Department of Defense database, his screen shows six numbers that appear to be IP addresses. (The first is 213.225.312.5.) The numbers between decimal points in an IP address, called "octets", are decimal representations of 8-bit numbers (8 binary digits of either 0 or 1). Therefore, the range of decimal numbers for an octet is 0 to 255, because 11111111 in binary is 255 in decimal. The IP addresses on Stanley's screen each contain one octet higher than 255 (such as 312 in the first example), which is apparently the filmmakers' way of ensuring that no one's real IP address appeared.
The original screenplay draft had a very different take on the Gabriel Shear character. He was first written as a mercenary whose plan for the stolen DEA funds had him joining forces with military and intelligence figures and planning to destroy corrupt politicians, and had several lengthy monologues in which U.S. agents listened to him and then joined his crusade on the spot. While the funding/covert war angle was maintained, Skip Woods later remade Gabriel Shear into a patriotic agent who seeks to destroy world terrorists, and who kills the Senator and his aide for trying to kill him and stop his plans.
2600 'The Hacker Quarterly' magazine was approached by Warner Bros. for permission to use their magazine and name in the film. WB was suing 2600 at the time for linking to the DVD deciphering program DeCSS. The magazine said no.
The office scene at the end, opens with a receptionist walking across the room with a pot of coffee, right before the bus crashes through the windows. The girl in that role is Erin Bradshaw. She was hired to work as a Production Asst. on the movie after walking up to the production trailer one day, and asking if they had openings. On the last day of shooting...the girl who was originally cast to play that part was stuck in traffic. The Asst Director called over to production, for "that blonde PA to get to set...STAT" when she arrived on set, they asked her to be the part of the receptionist in the movie.
The scene in which the school bus is swung was actually shot by hiring a group of people to sit in a bus, in front of a blue screen, while they swung the bus from a crane. According to the stunt coordinators, the same effect could have been portrayed for half the cost.
Trailers, television commercials, and print advertisements for the film all contained "passwords" which allowed viewers to play a contest game on the film's official website. A password also appears in the closing credits. (See "Crazy Credits").
Most of the cast have starred in films based on Marvel comics: Hugh Jackman and Halle Berry played Wolverine and Storm in the "X-Men" films. John Travolta later played Howard Saint in "The Punisher". Don Cheadle played Colonel James Rhodes in the "Iron Man" sequels. Vinnie Jones would go on to play Juggernaut in "X-Men: The Last Stand" working again with Hugh Jackman and Halle Berry and Zach Grenier would later play Mr. Sherman/Rafke in "Fantastic Four: Rise of the Silver Surfer".
This is the second film in which John Travolta makes a reference to the film "Dog Day Afternoon." In the opening scene, he discusses the film in great detail. And in "Saturday Night Fever," he impersonates Al Pacino's "Attica!" chant from the film. Coincidentally, Swordfish was released in 2001 and in Saturday Night Fever, "2001" is also the name of the disco where he dances.