Right after finishing Electronics vocational school I spent the next year working as an intern at Unicamp (Campinas University in Brazil). The job was at the computer lab of the School of Electrical and Computer Engineering[1]. This was before ethernet (yeah, I' that old), so dumb terminals were linked to the CPUs through RS-232 cables - when I was not burning my fingertips soldering DB-25 connectors I was tinkering with every computer I could get my hands on.

I saw /etc/passwd and asked my boss how to decrypt the passwords. He told me it was a one-way encryption, so the login program would just encrypt the password you provided and compare to the encrypted value. He went on explaining the old crypt algorithm and even made a bet I could not guess his password. He said it was related to a movie.

So at 17 I was hooked and started studying the sources. In the end I just patched and recompiled the passwd binary to store clean text passwords in a hidden file. Later I learned this was called a trojan horse.

And even now, 30 years later, I remember his face when I told the movie was Citizen Kane and his password was "rosebud".

Thank you Miguel and Gorgonio for teaching me about C and Unix! This knowledge paid my rent for 3 decades and I still love the job.

[1] http://www.internationaloffice.unicamp.br/english/teaching/g...

[2] https://en.wikipedia.org/wiki/RS-232