PGP freeware has evolved over time, with different versions and features added and removed. The source code is released for peer review, and users must verify digital signatures. The safest version is the original command-line version, while version 6.5.8 CKT by Imad Faiad is widely used and preferred due to added improvements. The current version is 9.x, which includes a transparent email proxy and a 30-day free trial.
Originally written by Philip Zimmerman in 1991, PGP freeware has spanned many generations, changed hands more than once, and had features added and then removed to be reserved for paid versions only. There are personal philosophies about which freeware PGP version is best and why.
The source code of PGP releases is released to the public for peer review purposes, to ensure that there are no “backdoors”. When you download the software, you must verify that a digital signature is included to verify its authenticity.
PGP version 2.6.2 (DOS/MacOS command line) freeware:
Purists argue that the original command-line PGP version is the safest to use, if not the most convenient. There are third-party graphical user interfaces (GUIs) that help automate the process to some extent, although third-party software can introduce security bugs. Therefore, most people attracted to version 2.6.2 will most likely not use a GUI. Advantage: very safe and very small program. Disadvantage: Requires manual use of the command line. Availability: Archive websites.
In 1996 Zimmerman partnered with Viacrypt, which later became PGP Incorporated. Windows 4x and 5x compatible versions followed, but the next watermarked version came after Zimmerman sold PGP in 1997 to Network Associates, Incorporated (NAI).
Version 6.5.8 freeware (NAI) included native email plug-ins for Outlook, Outlook Express, Netscape, and Eudora. For other clients like Pegasus Mail or Bat!, free third-party plug-ins were available. This release also included a Virtual Private Network (VPN) plugin. However, NAIs 6.5.8 was pre-XP and is no longer widely used.
After the 6.5.8 release, NAI decided to discontinue the practice of source code release. Zimmermann, who had been a consultant for NAI, left their employment over the disagreement. Version 7.x was unpopular and PGP languished. During this time, unaffiliated programmer Imad Faiad decided to use the source code of various 6.x releases to further develop the software himself. The result was the successful, albeit controversial version “6.5.8 CKT”.
Version 6.5.8 CKT Freeware (Windows 95/98/NT/2000/XP) by Imad Faiad:
Faiad has written several builds of v6.5.8, but build 08 is the most popular. It fixed the digital signature bug, made the version XP compatible, and re-added PGP Disk, the PGP volume encryption utility that was included in previous 6.x versions. He also added many other improvements, including the ability to use very large keys. “CKT” stands for “Cyber Knights Templar” and identifies this version of PGP as separate from that of NAI.
After NAI sold the PGP rights to PGP Corporation in 2002, Faiad was asked to stop development. Zimmermann’s dedication to providing the PGP source code was for security reasons, not to invite “competition” for official releases. The current source code is now released under these express conditions.
That said, the 6.5.8 CKT version remains widely used and many prefer it to the official releases due to the improvements added by Faiad. Advantage: XP compatible, with e-mail plug-ins included for Outlook, Outlook Express, Eudora and Netscape; VPN plug-in included, digital signature bug fixed; PGP Disk included along with other advanced features including support for very large keys. Disadvantage: Some people think it’s unwise to support an unofficial version. Availability: Archive websites.
Currently, Zimmermann is a consultant to PGP Corporation. This brings us to the current versions, starting with version 8.x, the first official version with compatibility with Windows XP.
Version 8.1 (all Windows and MacOS) by PGP Corp.:
The program looks a lot like an updated 6.5.8, but the native email plugins won’t work without purchasing a license, and a VPN plugin isn’t included. PGP Disk has been replaced by PGP Whole Disk, which is only available in licensed versions. Free third-party plug-ins can be used with non-Microsoft email clients, and free alternatives to PGP Disk are available for encrypting volumes and drives. Version 8.1 seems to be the most popular freeware release as of mid-2005. Benefit: Great looks, feature improvements, XP compatibility. Disadvantage: Native email plugins are no longer free, although free third-party plugins can be found for virtually all popular (non-Microsoft) email clients. Availability: Unofficial archive sites.
The most recent “freeware” version at the time of writing is the PGP Personal Desktop 9.x trial version. The most notable change is the move to a transparent email proxy, which replaces email plugins. The proxy scans mail ports for incoming or outgoing mail and encrypts/decrypts them without user intervention. This fully automated feature works free for 30 days, after which the program reverts to the 8.1 equivalent if a license is not purchased.
Version 9.x is a much larger download, weighing in at over 20MB, compared to 8.1’s approximate 7MB download. Despite its improved desktop interface, it doesn’t seem to be gaining popularity among PGP freeware aficionados compared to the 8.1 version of the watermark.
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