General :: How To Encrypt A Single File

I need to temporarily store a file containing sensitive data in a public server, in a secure way. I think that encrypting the whole file would be much more secure than creating a passworded .zip encrypted file, because they could be subject of brute force attacks. Attacking a whole file of unknow format is harder, I think. I thought of something like the command:

Code:
$ programidontknow --encrypt mysensitive.file --output-file mumblerumble.file
then the program asks interactively for a password)
$ ls
mysensitive.file mumblerumble.file

So I get one file that may look like junk. I tried to search how to do it with GnuPG. But it seems that GnuPG needs much configuration I dont want to do. I simply want to type the password one time to get the file. It doesnt need to retain any configuration for what I want to do. In similar scenario, I would want to do this on a machine/account that is not mine.