PGP vs GPG: what’s the difference?

PGP and GPG do the same job: they encrypt and sign messages and files. PGP is the original program, released by Phil Zimmermann in 1991,^[1] and today a commercial product line.^[2] GPG, short for GnuPG, is a free program.^[3] Both follow OpenPGP, the open standard based on PGP, so they can usually read each other’s keys and messages.^[4]

This guide explains each name, how they fit together, why the OpenPGP standard has recently split in two, and what that means when you swap keys with someone. For the basics of keys themselves, see what a PGP key is.

What is PGP?

PGP stands for Pretty Good Privacy. Phil Zimmermann released it as freeware in 1991. When it spread around the world, he became the target of a three-year US criminal investigation, because the government held that this broke US export rules for encryption software.^[1] After the government dropped the case in early 1996, Zimmermann founded PGP Inc.^[1]

PGP has changed hands several times since. Network Associates bought PGP Inc. in December 1997. In 2002 it stopped developing PGP and sold the rights to a new company, PGP Corporation.^[1] Symantec bought PGP Corporation in June 2010.^[5] As of November 2026, Broadcom’s Symantec division sells business encryption under the PGP name, such as PGP Encryption Suite, which encrypts disks, removable drives, email and files.^[2]

So “PGP” can mean three things: that commercial software, the open standard that grew out of it, or (most often) any key or message in that standard’s format, whichever program made it.

What is OpenPGP?

OpenPGP is the open-standard version of PGP’s encryption formats. It’s published by the Internet Engineering Task Force (IETF), which sets many internet standards, in its numbered “Request for Comments” (RFC) series.^[1] The standard spells out how keys, signatures and encrypted messages are built, so that programs from different makers can work together.^[6]

For nearly 17 years the main version was RFC 4880, from November 2007. In July 2024 the IETF replaced it with RFC 9580, which also supersedes two add-ons for the Camellia cipher and elliptic-curve keys.^[6] RFC 9580 makes the modern Ed25519 and X25519 algorithms mandatory for software to support, adds authenticated encryption (encryption with a built-in check that nothing was altered), adds Argon2 for protecting keys with a passphrase and introduces version 6 keys.^[6]

Keys in the format RFC 4880 required are called version 4 keys. RFC 9580 deprecates them: software should no longer create them, but should still accept them.^[6]

What is GPG (GnuPG)?

GPG is the everyday name for GnuPG, the GNU Privacy Guard. It’s a free implementation of OpenPGP that also supports S/MIME, a separate standard for encrypted email. It’s released under the GNU General Public License, so anyone can use, change and share it.^[3] Its developers have worked on it alongside the OpenPGP standard since 1997.^[7]

GnuPG itself is a command-line tool, run with the gpg command, and many other apps act as front ends to it.^[3] As of November 2026, the current version is GnuPG 2.5.24, from September 2026, and the older 2.4 series has reached end-of-life. On Windows, GnuPG’s developers also release Gpg4win, a fuller package than GnuPG’s own minimal installer.^[3] Our guide to Kleopatra shows how to use its main app.

Are GPG and PGP different?

Yes. They’re separate programs from separate makers: PGP is commercial software for organisations, sold by Broadcom,^[2] while GnuPG is free and open source.^[3] What they share is OpenPGP. Broadcom says all its PGP Encryption products use the OpenPGP standards, which makes them widely compatible with other PGP software.^[4]

In everyday use the names blur. A “PGP key”, a “GPG key” and an “OpenPGP key” are all keys in the OpenPGP format, whichever program made them. Here’s how the three compare:

Can GPG read PGP messages and keys?

Usually, yes, because both use OpenPGP formats.^[3][4] As long as you have the matching private key, a message encrypted with one program can normally be decrypted with the other. Our guide to decrypting a PGP message shows the steps on each kind of device.

The main exception is key types. As of November 2026, Broadcom’s knowledge base says its PGP Encryption products can’t import keys that use Curve 25519, though PGP Encryption Desktop can import elliptic-curve keys on the NIST P-256, P-384 and P-521 curves.^[8] That matters because RFC 9580 makes Ed25519 and X25519, both built on Curve 25519, mandatory for software that follows it.^[6] If you exchange keys with someone who uses Broadcom’s software, check which key types it accepts before you make or send a key.

Why is OpenPGP split in two?

Because the update to RFC 4880 split in two. The IETF published RFC 9580 in July 2024 as the official successor to RFC 4880.^[6] Werner Koch of g10 Code, the company that has maintained GnuPG since 2001,^[3] and Ronald Tse of Ribose publish a different update, called LibrePGP. Their draft names GnuPG as the leading open-source implementation of LibrePGP, and RNP, the library the Thunderbird email app relies on for encryption, as another.^[7]

LibrePGP first appeared as an Internet-Draft, a working document, in November 2023, and its latest revision came out in September 2026. It’s an individual submission, not an IETF standard. Its authors describe it as OpenPGP with a few newer algorithms and a focus on long-term stability, and say RFC 9580 “breaks with many concepts of former versions”.^[7] Projects that follow RFC 9580 include Sequoia PGP^[9] and OpenPGP.js.^[10]

GnuPG follows LibrePGP.^[7] As of version 2.5.24, released in September 2026, it also has an opt-in setting for organisations whose rules require RFC 9980, a set of post-quantum formats (designed to resist future quantum computers). In that mode it also supports Ed25519 and X25519 as RFC 9580 defines them. For everyone else who wants post-quantum protection, GnuPG’s developers recommend LibrePGP’s own algorithm, based on Kyber.^[3]

What does the split mean for you?

For everyday messages, often very little. Version 4 keys are common ground: LibrePGP calls them its preferred key version,^[7] and RFC 9580 tells software to keep accepting them.^[6] The differences are in the newest features. RFC 9580 adds version 6 keys and its own format for authenticated encryption. LibrePGP adds version 5 keys and a different encrypted-data format, and RFC 9580 defines neither.^[6][7] So a program that follows only one side may not read the other side’s newest keys and messages.

Some practical rules:

• Stick with version 4 keys for now if you write to people who use different programs, because both sides read them. A key’s fingerprint, the code that identifies it, shows its version: a version 4 fingerprint is 40 characters long (not counting spaces), while version 5 and version 6 fingerprints have 64.^[6][7]
• Ask before you switch. Before you make a version 6 or post-quantum key, check that the people you write to use software that can read it.
• Mind commercial PGP. If you or your contacts use Broadcom’s PGP Encryption products, avoid Curve 25519 keys for now.^[8]
• When something won’t open, ask which program and version the other person uses. It may be a key or message from the other side of the split.

Which other programs use OpenPGP?

Besides GnuPG and Broadcom’s products, OpenPGP implementations include:

• Sequoia PGP, whose library aims to implement RFC 9580 in full. The project also offers a command-line tool, sq, and a drop-in replacement for the gpg command.^[9]
• OpenPGP.js, a JavaScript implementation that follows RFC 9580.^[10]
• RNP, Ribose’s library, which Thunderbird relies on for encrypted email.^[7]

Mantis plans to include on-device OpenPGP tools, with PGP keys kept separate from its chat and wallet keys.