GPG4O

Features

The central functions of gpg4o at a glance. See for yourself.

Email encryption
  • Asymmetric encryption method
  • Private and public keys
  • Encryption by both keys
  • Readable only with private key
  • Confidential communication guaranteed
Outlook integration
  • Simple and secure
  • Seamless user experience through integration in Outlook
  • Encryption and decryption of messages and attachments
  • End-to-end encryption
  • Compatibility and widespread standard: Based on OpenPGP with a global user base
Key Server Management
  • Simple key distribution thanks to automatic synchronization
  • Exchange keys with local and public key servers
  • Central key management (requires Enterprise KeyServer)
  • Web of Trust – checking the trustworthiness of external keys using information from known key holders

Features

Support for key servers
Support for terminal servers
Microsoft Policy Manager and automatic key generation
Compatibility with Symantec Encryption (formerly PGP), Enigmail, KMail, Apple Mail, K9-Mail and iPGMail and more
Large user base (OpenPGP)
Support for working groups
Strong cryptography
Strong performance

System requirements

gpg4o requires Microsoft Outlook Microsoft Outlook 2016®, 2019®, 2021® or 365 in the Classic version and Microsoft Windows®. The following combinations are supported:

Operating system Outlook 2016 Outlook 2019 Outlook 2021 Outlook 365
Windows 10
Windows 11
Mac OS

Frequently Asked Questions

gpg4o is an add-in for Microsoft Outlook® that can be used to encrypt, decrypt, sign and check messages and their attachments. gpg4o uses GnuPG, a free encryption software.

gpg4o uses an asymmetric encryption method and follows the OpenPGP standard. This system uses key pairs consisting of a private and a public key. The private key is kept secret, the public key is passed on to your contacts. As soon as the public key of the other recipients has been received, it can be used to encrypt an email message to the recipients concerned. This message can then only be decrypted again with the recipient’s private key. You can find out how to send and receive encrypted and signed files in the manual.

gpg4o requires Microsoft Outlook Microsoft Outlook 2016®, 2019®, 2021® or 365 in the Classic version and an installed version of GnuPG v2.2.33 or higher. The necessary installation files can be found on the gpg4o product page. The steps required for installation are described in the manual. Windows 8® (32/64 bit), Windows 10® (32/64 bit) or Windows 11® (32/64 bit) can be used as the operating system. For detailed information, please refer to the System requirements page.

If the trial period is not long enough, we can extend it for you. Contact us at [email protected] You can still read your messages encrypted with gpg4o as long as you do not uninstall gpg4o. As soon as you have purchased a license for gpg4o and imported it, gpg4o can be fully used again within the scope of the purchased license without further installation.

When importing a license file, “No license file” is displayed or a license file, as an attachment to an e-mail, cannot be imported. If you encounter these errors, we recommend that you check whether you have installed GnuPG correctly and entered the path to gpg.exe/gpg2.exe correctly in the settings. If necessary, reinstall GnuPG on your computer.

If you remove the email account in Outlook that is linked to your license, gpg4o will no longer recognize your license. The add-in will then automatically switch to test mode.

I receive the license from the license management by e-mail and cannot import it. The following error message appears: “Your license does not match the current Outlook account. Please adjust your license in the gpg4o license management or contact the sales department.” Check whether the e-mail address in your Outlook is identical to the e-mail address in the license. The two e-mail addresses must be the same. If this is not the case, correct the e-mail address of your license via the gpg4o license management.

The license of gpg4o entitles you to use gpg4o with the licensed email address and other email addresses within the same installation for an unlimited period of time. During the product maintenance period, you have the option of contacting support if you have any questions or problems and obtaining and installing updates. Each license of gpg4o may be used simultaneously on several computers and in different profiles (e.g. desktop PC + laptop) as long as the licensed e-mail address is set up in Outlook on both computers. The term of the product maintenance and the possibility of using the license begin with the first download of the purchased license. If you intend to use gpg4o with different profiles within the same Outlook installation, please contact us.

If the product maintenance/support has expired, gpg4o can still be used. This means that you can continue to send encrypted/signed emails and read encrypted/signed emails. However, you will not receive any further updates from gpg4o.

By purchasing an extension of the product maintenance/support, you can continue to receive new updates for gpg4o. The gpg4o development team is constantly improving the program and integrating suggestions from customers into a new version. After purchasing an extended license, it must be imported into gpg4o once.

When updating gpg4o, only the program files are updated. Your GnuPG keyring and your gpg4o settings will be adopted.

Yes, importing and exporting keys is also possible via drag & drop.

Yes, gpg4o supports encrypted emails in HTML format.

gpg4o uses the PGP/MIME method to send encrypted emails. The PGP/Inline format is also supported.

If you send an e-mail and activate the options for “Encrypt” and/or “Sign”, these settings apply to both the text of the e-mail and its attachments. Only the subject line and the recipient list remain unencrypted. If desired, gpg4o encrypts only the attachment of a message.

Create a backup on your old computer with gpg4o. You can import this backup on the new computer after successful installation of gpg4o and GnuPG. Only save the backup on your own physical data carriers. The backup contains your personal data, so you should never upload the backup to the cloud.

If your computer is defective, you will no longer have access to your hard disks. You can no longer access the private keys, so you cannot decrypt old e-mails encrypted with these keys. To protect yourself from this, please create a backup. Only save the backup on your own physical data carriers. The backup contains your personal data, so you should never upload the backup to the cloud.

Do you have any questions about discounts for different customer groups (retailers, pupils and students, educational institutions or non-profit organizations)? Do you have any questions about the graduated prices of the individual products? If you have any problems or questions when purchasing gpg4o, please use the contact form or send an e-mail to [email protected]. Alternatively, you can contact support directly via Outlook in the gpg4o menu under “gpg4o help”.

If you have any problems or questions regarding the installation or use of gpg4o, please send a support request via “Contact”. Alternatively, you can contact support directly via Outlook in the gpg4o menu under “gpg4o help”. A log file will be sent automatically. A detailed error description with the steps taken before the problem occurred helps us to process your request more quickly.

So that our development department can eliminate any errors that may occur as efficiently as possible, status messages from gpg4o are written in so-called log files. These status messages do not contain any personal information, passwords or contents of emails. Before sending the e-mail with the log files, you can view the transmitted information by unpacking the attached .zip file. All files contained therein consist of plain text.

The option “Hide attachment names” is activated by default in gpg4o and increases the confidentiality of your emails by hiding the file name. If a recipient cannot process these file names, you can deactivate this option in the gpg4o settings. In gpg4o in the “Settings”/”Send/Receive Settings”/”Send Attachment Send Options” you can activate the option “Keep attachment names”, which increases compatibility with other OpenPGP implementations.

Svenja Winkler
CEO

How to contact us

How would you like to handle your sensitive data in the future?

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