Encrypted PDF’s

You create and use PDF documents all the time. Once in a while, however, you might need to send some sensitive information to someone in the form of a PDF doc. The best thing to do in that case is to encrypt the PDF. The Preview app is up to this task.


Preview Encryption

If you are emailing sensitive information to someone like a social security number, credit card number, etc you definitely want to encrypt the PDF document. You could use other document formats, but PDF’s are easily encrypted and can be locked down so they cannot be edited. The only hassle with this is you need to get the encryption password for the PDF to the other person via phone or text message. A phone call would be more secure (I think!). On the other hand, maybe this is a reoccurring transaction with someone. In that case, once the other party has the password you can just keep using the same password each time.

My Mac is setup to open PDF’s using the Preview app. I use other apps to work on PDF’s at times, but Preview is easy to use for basic file manipulation. To encrypt a PDF first open it in Preview:


Obviously, this is a fake document. Go to the “File” menu and choose “Export:”


Just check the box labeled “Encrypt:”


You will then get this drop down sheet asking for a password:


Enter the password twice and click “Save.” Your PDF will now display on your Desktop like this:


When you open the PDF file it will ask for the password:


After you enter the password the original document will open:

Yes, there are more sophisticated ways to password a PDF file using other software. If you are transmitting government secrets, it would be best to use more complicated encryption. However, for the rest of us, using Preview’s 128 bit encryption algorithm is quite adequate.


If you need to email an occasional encrypted PDF, using the Preview app is the logical choice.