If you map a binary variable into a, let's say, 128-bit number (non-linearly) where a mapping is unique for every encryption key used, there's nothing making it

If you map a binary variable into a, let's say, 128-bit number (non-linearly) where a mapping is unique for every encryption key used, there's nothing making it an anathema for encryption. I am not sure whether this is achievable practically though.