How to Use PGP Encryption & Sign Files
By Brian Richards
Updated September 28, 2017
The risk of losing confidential data worries many computer users, yet operating system and popular application solutions do not wholly solve the problem. Windows, for example, can encrypt whole disks or even folders, but the process for doing so is confusing and hard to understand. More importantly, the tools that are available for encrypting data do little to clearly present the problems and solutions of digital privacy. Phil Zimmermann wrote the software Pretty Good Privacy (PGP) with the intention of promoting awareness of privacy issues and making the job of encrypting and signing data files easy to accomplish.
Prepare to use PGP
Download and install PGP software from the International PGP Home Page. Follow the "download" link to choose a GNU Privacy Guard version appropriate for your operating system. Double-click on the installation file to install PGP on your computer.
Launch the PGP keys program to generate a key pair. Follow the "Key Generation Wizard," filling in your name and email address, and select a key pair size of 2048 bits. Select an appropriate key expiration date and a complex passphrase. When the wizard is complete, click on the check box to "Send my key to the root server now."
Distribute your public key to those with whom you would like to exchange encrypted messages and files. These people will need to have PGP installed on their computers, as well. In the PGPKeys application, right-click on the key with your name and select "copy." Open a new message in your email program, right-click in the message body and select "paste." The public key that others need to encrypt messages to you and decrypt message from you appears as text within the "key block."
Obtain public keys from those with whom you would like to exchange encrypted messages by requesting that they send you their keys via email or post their keys to a Web page.
Send encrypted messages
Create a new email message by launching your email program, selecting new message and entering message text in the message body.
Click within the message body to ensure that the cursor is visible, and right-click on the PGPtray icon in your system tray. Select "Current Window" and "Encrypt & Sign."
From the PGPkeys window that has been launched, select the key for the intended recipient of the message and click "OK." Enter the passphrase for your key and click "OK." The message text should be converted to a "PGP MESSAGE" block.
Create and save a file to be encrypted, such as a word processing document or a spreadsheet.
Launch the PGPTools application from the PGP Program Files folder.
Click on the "Encrypt' button and select your file.
From the PGP-Key Selection Dialog choose a recipient and click on "OK."
Note that the download link in References points to an older version of PGP. This version is freeware, whereas the latest version requires a license fee. Alternatively, PGP also distributes a free version called Gnu PGP (GPG), although this version is slightly more difficult to use.
Based in Pittsburgh, Brian Richards has been writing instructional guides and content for college courses since 1998. His courses are used by Penn State University and Westwood College. He holds a Master of Science in instructional technology from Bloomsburg University, and is pursuing a second in information security at Carnegie Mellon University.