For example I have the password X and I want to encrypt 2 different things. Even if one of them was stolen due to a keylogger, other will be completely safe. I wonder how safe something like this would be if the master key is completely random, secure and unknown. Also with what algorithm, program would i be able to do this on Linux systems?
I think something like this is possible actually because of Electrum's key generation method. It uses one master private key to generate all the addresses and private keys.