PGP Utility

A desktop app for OpenPGP: generate keys, encrypt and decrypt files and text, sign and verify. Windows, macOS and Linux.

Everything happens on your machine. There is no account, no telemetry, and no keyserver: your keys are never sent anywhere, because there is nowhere for them to be sent.

Why this exists

There is no shortage of OpenPGP tools. Most of them are one of two things: a command line that assumes you already know what a subkey is, or a GUI wrapped around a keyserver and a cloud account.

This one is for the case in between. You have a file or a message, you have someone's public key, and you want the thing done without learning gpg's flag syntax or signing up for anything. It tells you what it is doing in the words a person would use, it refuses the options that only make you less safe, and it says plainly when something cannot be verified rather than showing a green tick and hoping.

It is a sibling to resume-builder, and shares its position: a real desktop application that runs entirely on your machine and sends nothing anywhere.

What it does

• Files. Encrypt and decrypt, one file or a batch, with progress and cancellation. Drag and drop onto the window.
• Text. Encrypt, decrypt, sign and verify a block of text, which is what most PGP is actually used for. Pasting an encrypted or signed block selects the matching action.
• Sign and verify. Detached signatures, so the original file is untouched and someone without this tool can still open it. Clear-signed blocks for text.
• Keys. Generate Ed25519 or RSA, import, export, search. Fingerprints are grouped so you can actually compare them by eye.

Files	Text	Sign and verify

Cryptography

• AES-256, always. Not a setting.
• Every message carries an integrity check, and decryption verifies it. A file that fails is rejected and produces no output at all. This is what stops someone who cannot read your plaintext from flipping chosen bits in it.
• Ed25519 by default, with a Curve25519 encryption subkey. RSA is available at 2048 or 4096 bits for older tooling.
• Revocation certificates are generated when you create a key. Publishing one retires a key you have lost access to, and it cannot be created later, because creating it needs the private key and passphrase you would have lost.
• Keys are stored per-platform, and on macOS and Linux the key directory is 0700 and key files are 0600.
• Passphrases are held as character arrays and cleared after use. This narrows the window in which a passphrase sits in memory. It is not protection against a machine that is already compromised.

Interoperability with GnuPG is tested in both directions on all three platforms in CI, not assumed.

This project has not been independently audited. See SECURITY.md.

Install

On Windows, winget is the shortest route:

winget install Gentian28.PgpUtility

That installs 1.1.0, the current release. The community repository accepted the first submission on 2026-08-18, eighteen days after it was opened, and the 1.1.0 bump on 2026-09-21, thirty-four days after its own. A bump waits on that review each time, so the index can trail a new release here by a few weeks. The release below is always current.

Otherwise download from the latest release.

Platform	File
Windows	PgpUtility-win-Setup.exe, or PgpUtility-win-Portable.zip for no installer
macOS (Apple silicon)	PgpUtility-osx-Setup.pkg
macOS (Intel)	PgpUtility-osx-x64-Setup.pkg
Linux	PgpUtility.AppImage

Nothing needs to be installed alongside it. The .NET runtime is bundled.

The scary warning you are about to see

The downloads are not code-signed. A signing certificate costs a few hundred a year, and this is a free tool. Unsigned is not the same as unsafe, but it does mean your operating system will warn you, and hiding that would be worse than explaining it.

Windows shows a blue "Windows protected your PC" box. Click More info, then Run anyway.

macOS refuses on first launch, with "cannot be opened because the developer cannot be verified". Either:

• Right-click (or Control-click) the app, choose Open, then Open again in the dialog. The right-click matters: double-clicking gives you no Open button.
• Or open System Settings, go to Privacy & Security, scroll to the bottom, and click Open Anyway next to the message about PGP Utility.

Linux does not warn, but the AppImage needs the executable bit:

chmod +x PgpUtility.AppImage
./PgpUtility.AppImage

Verifying a download

Each release includes SHA256SUMS-<platform>.txt. Since nothing is signed, this is the check worth doing:

sha256sum -c SHA256SUMS-win.txt        # Linux
shasum -a 256 -c SHA256SUMS-osx.txt    # macOS

Get-FileHash PgpUtility-win-Setup.exe -Algorithm SHA256   # Windows, compare by eye

Code signing

An application to the SignPath Foundation free code-signing programme was declined in August 2026. The programme requires public adoption signals (stars, forks, independent references) that a newly published project does not yet have, and it will be reapplied for once the project has them. Until then the warnings above apply and the checksums are the verification that counts.

Where your keys are stored

Platform	Location
Windows	%APPDATA%\PgpUtility\Keys
macOS	~/Library/Application Support/PgpUtility/Keys
Linux	$XDG_DATA_HOME/pgputility/keys, or ~/.local/share/pgputility/keys

Set PGPUTILITY_KEY_STORE to put them somewhere else, such as a removable drive.

Build from source

Requires the .NET 8 SDK.

dotnet build PgpUtility.slnx
dotnet test PgpUtility.slnx
dotnet run --project src/PgpUtility.App

The GnuPG interoperability tests skip if gpg is not on your PATH. Set PGPUTILITY_REQUIRE_GPG=1 to turn a skip into a failure, which is what CI does.

Project layout

src/PgpUtility.Core/    Models and services. No UI dependency, so it is what the tests target.
src/PgpUtility.App/     Avalonia 11 desktop UI, MVVM via CommunityToolkit.
src/PgpUtility.Tests/   xUnit. Round trips, failure modes, permissions, GnuPG interoperability.
packaging/icon/         Icon sources, all generated by make-icon.py.

License

MIT