gpg4o vs Mailvelope

gpg4o is a Microsoft Outlook add-in for encrypting, decrypting, signing, and checking messages and attachments. It uses public and private keys under the OpenPGP standard, and supports encrypted HTML email, PGP/MIME, and PGP/Inline. Its key management can synchronize keys, use local or public key servers, and check the Web of Trust; central management requires Enterprise KeyServer. The product also supports terminal servers, Microsoft Policy Manager, automatic key generation, and working groups. When encryption is enabled, it protects message text and attachments, but not the subject line or recipient list. The current feature page lists Outlook 2024 or 365 Classic on Windows 11 and marks Mac OS unsupported. A limited free version is available without a time limit, and a 180-day trial is noted. The listed gpg4o plan costs €99.95 a month. After maintenance expires, users can still send and read encrypted or signed email, but they do not receive further updates.

Mailvelope adds client-side end-to-end PGP encryption to supported webmail. Its browser add-on works with Gmail, Outlook, WEB.DE, and other webmailers, and can encrypt or decrypt attachments within email, including with PGP/MIME. While composing, it can detect a recipient’s public key; signature mismatches can help identify phishing attempts. Users can export keys, manage multiple keyrings, and use Mailvelope or other key servers. The free private-user offering is independent from Google, but lacks PGP/MIME, Google Workspace integration, and customer service. Mailvelope states that it complies with GDPR and EU privacy laws. Business plans include a 14-day free trial without payment data. Monthly billing costs €3 per user per month; annual billing costs €32.40 per user per year. Paid subscriptions auto-renew and can be cancelled anytime. Business integrations include professional or premium email support options. Mailvelope is available as an extension and through the web.