Sneakers (1992) is by far one of the best nerd movise ever made. The cast is all-star. The science, aside from the major premise of the movie (you have to be willing to suspend some disbelief to watch any hollywood movie; why not the overall premise? it wouldn't be any worse than what you have to do to yourself to watch Snakes on a Plane) is tight. The acting is top-notch. The plot is complicated enough to hold interest, but simple enough to be reasonable.
The movie opens on Young Martin Bishop (Garrison Hershberger) and Young Cosmo (Jo Marr) hacking some bank accounts in order to make some amusing political contributions courtesy of various major figures in the Republican party. Bishop goes for Pizza; Cosmo goes home with the police. Amusingly, Bishop was saved from punishment by the highly-plausible failure of his Volkswagen Microbus to start.
Time passes; Bishop is now portrayed by Robert Redford, who is apparently engaged in a break-in. During this sequence we are introduced to the other members of his crew; Ex-CIA employee Donald Crease (Sidney Poitier), the blind audio technician "Whistler" (David Strathairn), electronics whiz and conspiracy wingnut "Mother" ((Dan Aykroyd) and low man on the totem pole, Carl (River Phoenix). The crew successfully breaks into a bank and twiddles some numbers; the next day Bishop goes to the bank, withdraws a hundred thousand in cash, and takes it upstairs. Bishop and his boys are revealed as penetration testing specialists ("pen testers") who test the security of installations for money.
Back at the ranch, a pair of customers meet with Bishop. They turn out to be government employees who know about Martin's background and original identity, which never got in trouble for his little financial fun in college. He is roped into collecting a piece of electronics hardware which supposedly contains the holy grail of cryptography, a method of factoring large primes instantaneously (or so the plot hints) but which results in a box that can break through any cryptographic system instantaneously. As we know, this is more or less theoretically impossible, and the use of one-time pad (OTP) cryptography would necessarily defeat it entirely, and the way encryption is used to secure connections and communications is utterly misrepresented in the movie to make the idea work.
This is what scares most nerds away from the movie; they complain about its poor science. Those who look past this plot point at the background details will find that said details are so rational that the decision of what to represent correctly and what to take license with was necessarily a conscious one - no slip-ups here. Regardless, Bishop is presented with carrot and stick; if he refuses to take the job, his past will be filled in. If he takes it, his record will be cleared. Unfortunately, the whole thing is a set-up and the truth of who is behind it will shake Bishop's convictions entirely.
If you are a computer nerd, if you are a tech geek, if you love electronics more than puppies, you need to see this movie.