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.KEY file extension

To open .KEY files on Windows, if the file is a presentation: open it on a Mac with Apple Keynote, or ask the sender to export it from Keynote to a more widely supported format (such as PDF) before you open it on Windows.

To open a .key file, first determine whether it is an Apple Keynote presentation or a PGP/GnuPG key file. Apple Keynote opens Keynote .key presentations; PGP/GnuPG tools import .key files that contain exported keys.

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Last updated: June 12, 2026

Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .KEY files

Use these platform-specific instructions to open .KEY files safely.

Windows

  1. If the file is a presentation: open it on a Mac with Apple Keynote, or ask the sender to export it from Keynote to a more widely supported format (such as PDF) before you open it on Windows.
  2. If the file is a PGP key export: import it using your OpenPGP/GnuPG tool rather than trying to open it as a document (it is typically meant to be imported, not “viewed”).
Full Windows guide

Mac

  1. Double-click the .key file to open it in Apple Keynote (if it is a Keynote presentation).
  2. If it does not open as a presentation, verify whether it is actually an exported OpenPGP key file; those are typically imported into GnuPG-compatible tools rather than opened in Keynote.
Full Mac guide

Linux

  1. If it is a Keynote presentation, you may need to open it on macOS with Apple Keynote or have it exported to another format; Linux desktop environments may recognize types via shared-mime-info associations, but that does not guarantee a full-featured editor/viewer is available.
  2. If it is an OpenPGP key export, import it using your GnuPG toolchain (the file is intended for import, not editing).
Full Linux guide

iOS

  1. Open the .key file in Apple Keynote for iOS (if it is a Keynote presentation) or request an exported format if you cannot open it.
Full iOS guide

Android

  1. If it is a Keynote presentation, the most reliable approach is to have it exported from Keynote (for example to PDF) on a Mac and then open the exported file on Android.
  2. If it is an OpenPGP key export, use an OpenPGP-compatible app that can import keys; the .key file is typically meant for import.
Full Android guide

Security notes

  • Do not import a .key file into your OpenPGP/GnuPG keyring unless you trust its source. Key files are used for identity and trust decisions; importing an attacker-provided key and trusting it can lead to verifying the wrong signatures or encrypting to the wrong person.
  • Treat unexpected .key email attachments cautiously: the extension is ambiguous (presentation vs cryptographic key export). Confirm with the sender what it is supposed to be before opening or importing.
  • Keynote files are documents handled by complex parsers; if the file is untrusted, consider opening it in a safer workflow (for example, on a non-critical machine or after requesting a PDF export) to reduce exposure to document-parser vulnerabilities.

If you did not expect this file

This extension is usually plain data, text, or structured content—not a program by itself. The practical risk is social engineering (a scam attachment or misleading filename). For trusted senders you rarely need heavy-handed antivirus wording; use these tools when you want an extra check on unexpected downloads.

Avast

Avast offers free and premium antivirus software that protects against viruses, malware, ransomware, and phishing. Scan files before opening them to ensure safety.

Norton

Norton 360 delivers comprehensive antivirus protection, VPN, and identity theft monitoring. Scan files for threats before opening to keep your device secure.

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Can't open this file?

These are the most common causes and fixes when .KEY files fail to open.

Common reasons

  • The .key file won’t open (wrong type of .key)
  • Linux desktop shows an unexpected app for .key files
  • Someone sent me a .key but I only need to view it

Fix steps

  1. Confirm what you received: was it meant to be a presentation (slides) or a cryptographic public key for encryption/verification?
  2. If it is a PGP/GnuPG key file, import it using your OpenPGP/GnuPG tool rather than opening it as a document.
  3. If it is a Keynote presentation and you are not on macOS/iOS, ask the sender to export it from Keynote to a widely readable format (such as PDF) for viewing.

OS-specific troubleshooting

What is a .KEY file?

A .key file is best known as the native document format for Apple Keynote presentations. In other workflows, .key is also used as a filename for exported OpenPGP keys (for later import), even though the extension is not exclusive to that purpose.

Background

Apple Keynote uses .key as the file extension for its presentation documents. In everyday use, a .key file typically contains slides, layouts, and presentation content created in Keynote.

Common MIME types: application/vnd.apple.keynote

Further reading

Authoritative resources for more details on the .KEY format.

Common .KEY issues

The .key file won’t open (wrong type of .key)

.key is most commonly a Keynote presentation, but it is also used for exported PGP/GnuPG keys in practice. If you try to open a PGP key file in a presentation app (or vice versa), it will fail or look like gibberish.

  1. Confirm what you received: was it meant to be a presentation (slides) or a cryptographic public key for encryption/verification?
  2. If it is a PGP/GnuPG key file, import it using your OpenPGP/GnuPG tool rather than opening it as a document.
  3. If it is a Keynote presentation and you are not on macOS/iOS, ask the sender to export it from Keynote to a widely readable format (such as PDF) for viewing.

Linux desktop shows an unexpected app for .key files

On Linux, file opening behavior depends on MIME type detection and extension associations, which are often managed through the shared-mime-info database. If the association is incorrect, double-click may open the wrong tool.

  1. Right-click the file and choose “Open With…” to select the correct application for this specific file.
  2. If it is a Keynote presentation but you lack a suitable viewer/editor, open it on macOS with Keynote or request an export (e.g., PDF) from the sender.
  3. If it is a PGP key export, use a GnuPG-compatible key management/import tool instead of a presentation app.

Someone sent me a .key but I only need to view it

Keynote presentations are best viewed in Keynote, but many recipients only need a read-only copy. Converting/exporting from Keynote avoids platform and compatibility issues.

  1. Ask the sender to open the file in Apple Keynote and export it to a viewer-friendly format (commonly PDF).
  2. If you need to present and not edit, request an exported format that preserves appearance closely.
  3. Keep the original .key if you may need to edit later in Keynote.

FAQ

What is a .key file most commonly?

Most commonly, .key is an Apple Keynote presentation file used by the Keynote presentation software.

Why did my .key file open in a crypto app (or won’t open in Keynote)?

Because .key is also used in practice as a filename for exported OpenPGP/GnuPG keys meant for later import. If the file contains a PGP key export, it is not a presentation and should be imported into an OpenPGP/GnuPG tool.

Is there an official MIME type for Keynote .key files?

Yes. IANA registers application/vnd.apple.keynote for Apple Keynote documents.

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