Password Protect file or lock file from command line

Question

I need to lock a file where if anyone tries to open it then it requires a password. I would like for even root to have to type in a password different from the root's password itself. I'm not sure this is possible but any help would be appreciated. Thanks

Answer 1

You could use for instance:

mcrypt filename

it will ask you for a passphrase. To decrypt the file you should use:

mcrypt -d filename.nc