You can obscure your decrypter as much as you want, but what
would you gain? To decrypt the password, one doesn't need
the source of the decryptor. All you need is a copy of the
script, with the encrypted password. Somewhere in that script,
the password will need to be decrypted before sending it to
whatever application. Just put in a
near that place, and run the program. Or maybe you don't even
need to modify the code. Running and tracing it may be more
than enough.