Gpg4win
Gpg4win: A free, open-source Windows toolkit for OpenPGP and S/MIME email encryption. Ranked #18 of 29 in Email Encryption Software by our editors (7.4/10); pricing: Free plan; best for free open-source Windows OpenPGP and S/MIME.
At a glance
- Editor score7.4 / 10
- PricingFree plan
- Best forFree open-source Windows OpenPGP and S/MIME
- Free planYes
- Paid fromFree
- Secure deliveryAttachment
- Facts checked21 Sep 2026
Where it wins
- Supports both OpenPGP and S/MIME encryption and signing
- Integrates with Microsoft Outlook, Exchange, SMTP, and IMAP
- Encrypts files and folders through Windows Explorer
Where it doesn't
- Limited to Windows
- Uses attachment-based encrypted email workflows
- Local application rather than a hosted secure-delivery portal
Our verdict on Gpg4win
Gpg4win is a free, open-source Windows distribution of GNU Privacy Guard for encrypting and signing email and files. It is designed for individual users, organizations, and public-sector teams that need local cryptographic tools rather than a hosted email-encryption service. The package includes GnuPG, the Kleopatra certificate manager, the GpgOL Microsoft Outlook add-in, GpgEX for Windows Explorer, and related tools. It supports OpenPGP and S/MIME, with identity-based recipient verification, email signing, encrypted attachments, file and folder encryption, and cryptographic checksum creation and verification.
Its strongest fit is the Microsoft email ecosystem. GpgOL brings email signing and encryption to Microsoft Outlook, while support for Microsoft Exchange Server, SMTP, and IMAP covers common email transport paths. Kleopatra handles certificate management, and smartcard support is available for both OpenPGP and S/MIME. Windows Explorer integration adds file and folder encryption outside the email client, giving users a broader local encryption toolkit than an email-only add-in. These capabilities make Gpg4win suitable when teams want control over keys, certificates, files, and messages within a Windows desktop environment.
The trade-off is its delivery model and platform scope. Gpg4win is a local Windows application, and its secure email workflow is based on encrypted attachments rather than a hosted portal. Organizations looking for browser-based delivery, a hosted recipient experience, or broader platform coverage should choose a different type of service. Gpg4win is a strong choice for users who specifically need free, open-source OpenPGP and S/MIME tools on Windows, especially alongside Outlook, Exchange, or Windows Explorer. It is less suitable for teams seeking a cloud-managed encryption service or a platform-neutral workflow.
Your product? Our editors can test Gpg4win in depth and publish a review, labelled as paid · from $149/mo →
Gpg4win pricing
Gpg4win fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| Secure delivery | Attachment |
| Recipient verification | Identity |
| Message expiry | Not verified |
| Attachment limit | Not verified |
| Outlook integration | Yes |
| Gmail integration | Not verified |
| Admin access controls | Yes |
| Deployment | Desktop |
| Platforms | Windows |
| Support | Community, Docs |
| Built for | Solo, Small business, Mid-market, Enterprise (editorial estimate) |
| Integrations | 4 integrations: Microsoft Outlook, Microsoft Exchange Server, SMTP, IMAP |
| Pricing | Free plan |
| Website | gpg4win.org |
| Facts checked | 21 Sep 2026 |
Gpg4win integrations
Gpg4win lists 4 integrations on its own site.
- Microsoft Outlook
- Microsoft Exchange Server
- SMTP
- IMAP
Alternatives to Gpg4win
- FlowCryptA broad OpenPGP option for Gmail and mobile users, with enterprise controls for managed deployments.9.4
- c.EmailA free, open-source option for encrypted Gmail and Outlook email.9.2
- MailvelopeA browser-based OpenPGP option with broad webmail support and organization controls.9.0
See all Gpg4win alternatives →
Used Gpg4win? Be the first to review it
The editor score above is our own research. What this page doesn't have yet is a reader's view — what you used Gpg4win for, what worked and what didn't. No stars are seeded and no review is paid for; an editor reads every one before it appears.
Write a reviewTwo minutes · verified accounts only · read by an editor before it appears
Featured on iTechGuides
Gpg4win is listed in our Email Encryption Software directory. Add the badge to your site — it links back to this page.
<a href="https://www.itechguides.com/products/gpg4win/"><img src="https://www.itechguides.com/best/badge/gpg4win.svg" alt="Featured on iTechGuides" width="230" height="46"></a>
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.
Last updated · How we research and update