1) films often use the "aha, now I'm really serious" gimmick, wherein the "hacker" is now talking about some technique that he hadn't used before. There are rarely authentic justifications for this in reality. See, for example, the last 20 minutes of "Swordfish" ... "That's 2048 bit RSA... not even I could crack that!". Please don't do that.
2) Anecdotal: the best hackers I know shun jargon. Jargon-heavy dialogue always feels condescending. Anywhere you feel tempted to use impressive-sounding jargon, consider that the hacker would consider such a thing commonplace and would consider it implicit in any conversation with another hacker. Another analogy: you wouldn't write Bruce Lee in a role where he expounds in detail about his punches and kicks as he's fighting; apply the same aesthetic and you'll do fine.
3) The technical details of "Hacker Speak" are almost impossible to make authentic to your audience because there are so many different specializations. I could wax on about, e.g., high performance numerical computations but wouldn't know how to synthesize authentic talk about cryptography. On the other hand, I would probably be able to pick out inauthentic talk about cryptography pretty easily. Spotting fakes is a lot easier than creating plausible technical dialog. My recommendation would be to elide as much of the technical story as possible, and focus any programming-related dialog on the "three chief virtues" of a programmer: "laziness, impatience, and hubris" (coined by Larry Wall, I believe). To put it in more accessible terms: your hacker should always be thinking "How can I accomplish this task with the least human work possible (laziness)? How can I engineer it to go faster (impatience)? Is there really any reason why I couldn't write a program to solve problem X (hubris)?"
Anyway, I've had some experience with the film/TV industry (lived in LA for many years) so if you have any specific questions I'm happy to expand in email (see my profile for my address).
Good luck!