My dad added parental controls to our PC sometime around 1997. It also had Eudora installed, which my dad used for email. Poking around, I found the ini file th

My dad added parental controls to our PC sometime around 1997. It also had Eudora installed, which my dad used for email. Poking around, I found the ini file that had the ciphertext of the password for the email server. On a whim, I made another account in Eudora and put the ciphertext in as my password. In the ini, the plaintext of the password came out; I guess Eudora used some symmetric rot16 or xor like cipher! The same password worked to unlock parental controls, which had taken me just about a week to circumvent.