We send emails and attachments all the time.. we don't really think about the security of these attachments, we just assume that only the eyes of the sender and the receiver will see them. You may even have an encrypted or secure email connection, but realize that email transmission is only as secure as the weakest layer in the transport of the email. This layer may and most likely will be completely out of the sender or receiver's control.
One way we can help to combat this is to "zip" or compress files/folders and apply a password to the zipped file (archive) before it gets attached and sent. Then, you could attach the password protected zip file and send the password in a separate email (or better yet, call the recipient and TELL them what you're going to be using for the password).
So, how do we password protect a zip file? Let's see if we can explain it step by step using a nice free utility called 7zip.
Firstly, we need to have 7zip installed on our computer. You can get 7zip by downloading the executible file from http://www.7zip.org.
Once you've downloaded and installed 7zip, it's time to get zipping!
If I have multiple files I would like to send in one email, I like to create one folder and put them all in that folder. That way, I can just add that folder to the archive (zip file) and all files inside will be done in one fell swoop.
So, I have my folder with files in it. Now, right click on the folder and select 7zip, then Add to archive...
Next, change the archive format to zip, the encryption method to AES-256 (which is a stronger encryption), and if you like, check the "show password" box and enter your password for the archive (otherwise you'll have to enter the password twice. Next, Click OK.
That's it! Now simply attach your newly password protected .zip file to your email and send it off. When the recipient attempts to extract the zip file, they will be prompted for the password!