I want a colleague of mine to send me a sensitive MS-Word document via e-mail. Since Word's encryption is questionable, I would like to encrypt the file using a passphrase.
Do you know of any user-friendly encryption tool that a novice user can easily use? I wouldn't like to prompt for keys or anything like this - just provide simple interface for single file encryption.
I have solved this using Putty Secure Copy, through a Linux box I have somewhere. The user downloaded scp to the same directory where the file was, and I have send him the exact scp command by mail. Nice!
I have some additions (mainly the usage of winscp and perhaps virtual machines). My detailed answer appears below, as requested in comments.