Assign a Password To Zip Files
If you email around files a lot and are concerned about “prying eyes” seeing you attachments, consider zipping the attached file with a password.
Virtually all zip programs (outside the built in Windows client) allow you to assign a password in their zip dialog.
The security on the password is virtually unbreakable outside of brute force methods, so rest assured your files will be protected.
Just make sure if you do email the zip file protected with a password that you do not include the password in the body of your message!