PGP Virtual Disk is an on-the-fly encryption (OTFE) system that allows one to create a virtual encrypted disk within a file.

Older versions for Windows NT were freeware (for example, bundled with PGP

Pretty Good Privacy

Pretty Good Privacy is a data encryption and decryption computer program that provides cryptographic privacy and authentication for data communication. PGP is often used for signing, encrypting and decrypting texts, E-mails, files, directories and whole disk partitions to increase the security...

 v6.0.2i; and with some of the CKT builds of PGP). These are still available for download, but no longer maintained. Today, PGP Virtual Disk is available as part of the PGP Desktop product family, running on Windows 2000

Windows 2000

Windows 2000 is a line of operating systems produced by Microsoft for use on personal computers, business desktops, laptops, and servers. Windows 2000 was released to manufacturing on 15 December 1999 and launched to retail on 17 February 2000. It is the successor to Windows NT 4.0, and is the...

/XP/Vista

Windows Vista

Windows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...

, and Mac OS X

Mac OS X

Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

.

See also

• Disk encryption software
  Disk encryption software
  To protect confidentiality of the data stored on a computer disk a computer security technique called disk encryption is used. This article discusses software that is used to implement the technique...
  
  
• FreeOTFE
  FreeOTFE
  FreeOTFE is an open source on-the-fly disk encryption computer program for PCs running Microsoft Windows, and personal digital assistants running Windows Mobile . It creates virtual drives, or disks, to which anything written is automatically encrypted before being stored on a computer's hard or...
  
   – open source
  Open source
  The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
  
   alternative which supports MS Windows, Windows Mobile
  Windows Mobile
  Windows Mobile is a mobile operating system developed by Microsoft that was used in smartphones and Pocket PCs, but by 2011 was rarely supplied on new phones. The last version is "Windows Mobile 6.5.5"; it is superseded by Windows Phone, which does not run Windows Mobile software.Windows Mobile is...
  
   and Linux
  Linux
  Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
  
  
• TrueCrypt
  TrueCrypt
  TrueCrypt is a software application used for on-the-fly encryption . It is free and open source. It can create a virtual encrypted disk within a file or encrypt a partition or the entire storage device .- Operating systems :TrueCrypt supports Microsoft Windows, Mac OS X, and...
  
  
• United States v. Boucher
  United States v. Boucher
  In re Boucher, No. 2:06-mj-91, 2009 WL 424718, is a federal criminal case in Vermont, which was the first to address directly the question of whether a person can be compelled to reveal his or her encryption passphrase or password, despite the U.S. Constitution's Fifth Amendment protection against...
  
  – federal criminal case involving PGPDisk-protected data