I own it on DVD and just watched the special feature a couple weeks ago. It was really interesting to hear them talk about the research for the script, including getting Prof Adelman (the A in RSA) to consult on the lecture the mathematician was giving, and even to draft slides for him to present, which were not used in favor of projecting a sea of equations on a white background
There are other cool tidbits in there, they got an phreaker (sp?, phone hacker) who had done time in prison to consult as well. His nickname irl was Captain Crunch, and when they sort through the guy's garbage (the guy who's office they need to break into, played by the same actor as Action Jack Barker in Silicon Valley), they pull out a captain crunch box
The term you're looking for is "phone phreak". There's another reference to John Draper (Captain Crunch) early in the movie. When they are playing Scrabble, one of the words is SCRUNCHY - and the S and Y are separated from the rest of the word at first, so you see CRUNCH.
John was also a technical consultant for the film and appears in the documentary on the DVD.
For those who don't have it yet, I definitely recommend getting the DVD for the special features.
That was the article that inspired me to visit the San Francisco State University library to study the Bell System Technical Journal and copy down the in-band signaling frequencies to make my own blue box:
I was in awe that the phone company had published all the information we needed to hack into their system.
It was a fun time. I got to be friends with phreaks like Mark Bernay and John Draper (Captain Crunch) - although less of a friend after John wanted me to "work out" with him...
We had two phone lines at home, and one time I made an 800 call from one line, got into the tandem and started routing the call back and forth across the country and up and down through Canada and Mexico, and finally called the other line. I wanted to see how long a delay I could get when I said "hello" into one phone and hear it in the other. It was a full second!
Later a friend was visiting who was studying Russian, and I said "why don't we call the Kremlin!"
My automated dialing tricks only got me as far as Italy. So I rang an Italian operator and explained that I was an American operator trying to place a call to the Kremlin, and could she route the call for me? And she did!
The Kremlin switchboard connected us to an English translator, and we chatted a while. We explained that we were phone phreaks who used a blue box to place the call and how we routed it through Italy.
He asked, "is that like ham radio where you get a license from the government to do this?" We said, "yeah, sort of like that."
Eventually I got busted. I was living with my parents in Pacifica and had my electronics and programming lab in their basement. This was before personal computers, of course, but I was working for Tymshare and had a Teletype at home so I could dial into their machines in the off hours.
When I got home from work one afternoon, a couple of phone company investigators and a police detective were in the living room, sipping tea. My grandmother was visiting and she had served refreshments while they waited for me.
After some small talk, I gave them a tour of the basement lab. They didn't arrest me or anything, just took a circuit board or two and said "we'll be in touch."
I had to go to court and paid $25 restitution to Pacific Bell, a $150 fine, and yikes, $450 in 1972 dollars to my lawyer who pleaded nolo contendere for me.
Afterward, the investigators felt bad about it. They said the last guy they'd caught had been a real jerk but I seemed like a nice kid. So they took me out to lunch at my favorite Chinese restaurant!
I eventually ran into Captain Crunch again at the 2013 Homebrew Computer Club reunion. He didn't recognize me at first, but I mentioned that we used to hang out at his Berkeley apartment and smoke pot and hack on Forth code into the night.
There are other cool tidbits in there, they got an phreaker (sp?, phone hacker) who had done time in prison to consult as well. His nickname irl was Captain Crunch, and when they sort through the guy's garbage (the guy who's office they need to break into, played by the same actor as Action Jack Barker in Silicon Valley), they pull out a captain crunch box