Server Security: Keeping Your Data Safe Page 2
By Karl Magsig
When first installed and configured, PGP creates a key-pair using a specified passphrase. As the name implies, this key-pair is made up of two keys, one private and one public. You then share the public portion of your key-pair with others whom you allow to decrypt your messages.
The retail version of PGP also comes with a feature called PGP Disk. This feature allows you to create a folder on your hard drive, store and access data in it as normal, then when you are finished with it, encrypt the folder and all of its contents. Once it's been encrypted, the folder appears to the operating system as a file. The only way to gain access again is to "mount" it through PGP and enter your secret passphrase. Once PGP accepts your passphrase, it decrypts the folder and all of its contents, allowing you access to it as if it were a normal folder on your hard drive.
Other methods of data encryption are available, but PGP is the most widely used and recognized as well as the industry leader.
In this scenario, the transmission itself is not secure; it is still susceptible to being intercepted. If it is intercepted though, the data itself is completely illegible. Multiple public keys can be used to encrypt a single document; multiple recipients can decrypt the information as long as they have one of the appropriate private keys and the correct pass phrase. For more information on PGP security, visit the PGP security web site at http://www.pgp.com.