Secure communications is pretty easy actually- I can give my pgp signature and anyone could send me a message using it which would take even the NSA quite a while to crack. My public key (which is also on a number of key servers):
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1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=0nhE
-----END PGP PUBLIC KEY BLOCK-----
Using pgp, anyone could send me a message that only I (with my secret key) could decrypt. Not sure which program is best on Windows, but
http://www.gpg4win.org/ should work well.