They're not on the roof for that scene; they're in his office, using the computer room's air conditioning as a sound mask (and using a Cray Y-MP as a bench). While the movie takes some very early-90s liberties with technology (especially the scene where they use the chip), it's remarkably respectful of hacking -- there's a stronger emphasis on social engineering then the purely technical, and my "head canon" is that the chip itself is a quantum chip capable of breaking any then-known encryption.

No, the roof: https://m.youtube.com/watch?v=Xk0Mzci2Sks

> breaking any then-known encryption

(Also from fuzzy memory) Any then-known Western encryption. The chip was supposedly useless on Soviet/Russian encryption techniques, thus emphasizing who exactly the chip was meant to be used against.

It's also remarkably respectful of Bay Area geography -- they got the major bridges right. None of that Dustin Hoffman going the wrong way on the Bay Bridge stuff.

So much so that it arguably accelerated the introduction of the Clipper Chip by unimaginative spooks only a year later.

https://en.wikipedia.org/wiki/Clipper_chip

For me the biggest Hollywood liberty taken is the beautiful ASCII Colourized UIs for federal agencies and ATC that they reveal with the decrypt!

> it's remarkably respectful of hacking

This is one of my favorite things about the movie, and why I always recommended it to my security friends.

Anyone interested in learning more about social engineering should check out "The Art of" books by legendary hacker Kevin Mitnick.