PGP Email Encryption in Outlook

If you have basic questions about PGP encryption, see here for more information.

To use PGP in Microsoft Outlook, we recommend the free software Gpg4win, developed on behalf of the Federal Office for Information Security (BSI).

Gpg4win supports Windows 10 and Windows 11.

Supported Outlook Versions

• Classic: Outlook 2003, 2007, 2010, 2013 (32-bit) – direct encryption/signing via GpgOL plugin possible
• Modern: Outlook 2016, 2019, 2021, and Microsoft 365 – no stable GpgOL integration for 64-bit; encryption/signing done via Kleopatra or as encrypted file

Creating a Key Pair and Importing Contacts

1. After installing Gpg4Win, open the program Kleopatra.
2. Go to File → New Certificate.
3. Select Create personal OpenPGP key pair.
4. Enter your name and your mail.co.uk email address and click Next.
5. Review the information and click Generate Key.
6. Set a strong passphrase, which will be needed for encrypting and decrypting emails.
7. Click OK; your personal key will be created.
8. You can send the public key via email or upload it to a public key server. Finish the wizard with Finish.
9. Your key now appears in the list.
10. Import the public key of your communication partner via Certificates → Import Certificate to send encrypted messages.

PGP-Encrypted Emails in Classic Outlook Versions (2003–2013)

1. Open Outlook and compose a new email.
2. The GpgOL tab will appear in the menu bar.
3. The functions Encrypt, Sign, Decrypt, and Verify Signature are available.
4. Encryption is only possible if the recipient's public key exists in your GPG keyring.

PGP-Encrypted Emails in Modern Outlook Versions (2016+)

Direct integration in Outlook (64-bit) is not reliable. Practical method:

1. Compose the email in Outlook.
2. Save the email as a draft or file (e.g., .eml).
3. Open Kleopatra, select Sign/Encrypt → Encrypt/Sign Files.
4. Choose the saved email file and the recipients.
5. After encryption, the file will be saved as a *.gpg encrypted file.
6. Send the encrypted file via Outlook as an attachment.
7. The recipient needs your public key to decrypt the message.
8. To decrypt received messages, open the encrypted file in Kleopatra and enter your passphrase.

Important notes:

• Always back up your private key and passphrase in a secure location (USB stick, external drive).
• You can import public keys of your contacts via Kleopatra → Import Certificates.
• This procedure ensures that PGP/OpenPGP can be used compatibly with modern Outlook versions.