I'm not a Cryptography expert, but i've seen this topic sometimes on the Web: Master decrypt keys.
Most of the people said that "Master decrypt key" does not exist.
This makes sense if you developed your own Cryptography software.
But if a company releases a cryptography software, where the user must enter the content (string or file), and a password, and then he gets the output, wouldnt the company be able to include the user password in another string encrypted with the company's password in somepart of the file? so no matter the user has encrypted the file with 30 keys, the company could decrypt it's part of the file and get the user key to decrypt the entire file
does it make any sense? I was wondering this for security reasons