In 'Three Days of Condor', Robert Redford's character locates the hotel room of a professional hitmat (who is after him) by going to a locksmith and asking him "which hotel and room this key belongs to?" and the locksmith asks him "are you in the trade?" and he responds, "No, but I read a lot".
It's a serious hacker film, actually. Redford is the ultimate hacker in that film: social engineering, picking locks, scrambling MaBell's circuits, and taking out the bad guys in the CIA.
I have to disgree here regarding the film's merit. There are a few quite interesting (and unique) films in that genre from the 70s that are little known to today's audiances. Most came out around Watergate ~'74 (so were topical in those days) but then have been kind of memory holed.
The Kremlin Letter, 1970 (https://www.imdb.com/title/tt0065950/) - I recall someone saying this film really shows the ugly underbelly of intelligence services. This is an interesting film but it is very dark and somewhat disturbing. This one predates Watergate - it is a Cold War spy flick and makes Smiley's People look warm and cuddly ..
The Conversation, 1974 (https://www.imdb.com/title/tt0071360/) - Gene Hackman's character resurfaces a couple decades later in Enemy of the State (1998).
"memory holed" implies a deliberate coordinated attempt by the mass media and/or powerful actors to suppress some information they don't want knocking around the ether
