Best Email Encryption Software for Linux

Proton Mail is the simplest way to protect your communications with built-in end-to-end encryption. Prevent data breaches, stay compliant with regulations like GDPR and HIPAA, and earn client trust. Protected by Swiss privacy laws and trusted by over 50,000 businesses, Proton Mail keeps your business data confidential and under your control. With Proton Mail and Calendar, your team can securely manage their inbox and schedule, while your organization maintains a professional presence with support for custom email domains and personalized branding. And with the Easy Switch tool, migrating from Google or Microsoft is seamless, no IT expertise required.

Mailfence is an encrypted email service that offers OpenPGP based end-to-end encryption and digital signatures. Mailfence comes with a plethora of features that boost collaboration without compromising security and convenience. Mailfence documents allow you to safely store and edit documents, you can also share docs with your team with the push of a button. Mailfence calendar will keep your tasks, meetings, and events all in one secure place. Mailfence contacts will store your contacts and it will give you the ability to create mailing lists to maximize efficiency. We designed Mailfence to be a fully interoperable suite, which means you can synchronize Mailfence with most services out there. Mailfence business offers fully customizable whitelabel versions of the Mailfence interface. To put the cherry on top, Mailfence donates 15% of revenues of PRO subscriptions to IFF and EDRI to bolster the fight for Online privacy.

Tuta offers a highly secure, encrypted email, calendar, and contacts service designed to give users complete control over their data. With end-to-end encryption powered by quantum-safe cryptography, Tuta ensures that all your communications are private and safe from surveillance. The platform is easy to use, supports mobile apps for Android and iOS, and is ad-free, offering a seamless experience across multiple devices. Tuta is committed to using renewable energy to power its servers, ensuring privacy while contributing to a greener future.

RMail® is the e-security platform by RPost®, a global leader since 2000. RMail specializes in elegantly easy to use email encryption for privacy and compliance, e-signatures, legal e-delivery proof, secure file sharing, email impostor protection, document rights management, and AI-infused services to prevent data leaks and human e-security errors. RMail’s transmission e-security services are most often used by businesspeople or business systems that send important, sensitive, or consumer-regulated information. These RMail services are generally applied to those messages where the sender needs functionality beyond standard email in terms of (a) easier to use and more automated email encryption for privacy compliance, (b) returning a verifiable proof record of who said what to whom by email, (c) assurance and peace of mind related to delivery and open status of important and time-deadline email, (d) need a timestamped proof of content delivered, (f) need to share large files securely.

EncryptTitan is a 100% cloud based encryption system for MSPs & Enterprises that allows users to exchange information securely via email.  EncryptTitan provides organizations with the tools needed to adhere to state and federal privacy regulations while protecting their organization. EncryptTitan has pre-built DLP policies and settings that will look for regular content in the message body or attachment to automatically encrypt messages. Meet compliance requirements for protecting sensitive, private information. Providing data breach protection and avoiding costly fines and penalties. The outlook plug in can be used with our keyword encryption deployment, where the user can select which emails to be encrypted for the add in. EncryptTitan helps the safeguarding of private information & avoidance of litigation & bad press which can impact customer trust. Book your demo today and learn more about EncryptTitan.

Aster Mail is a free, open-source, end-to-end encrypted email service for people who want real privacy without the technical overhead. All encryption happens on your device before anything reaches our servers, so we have zero access to your messages or metadata. Aster uses standard OpenPGP with portable RSA-4096 keys, so you're never locked in. Your keys work with GPG, Thunderbird, or any PGP client, and they're discoverable through WKD and public keyservers. Aster-to-Aster messages use a Signal-inspired X3DH and Double Ratchet protocol for forward secrecy. Every plan includes encrypted email, custom domain support, free aliases, tracker protection, and full access across web and desktop. The entire codebase is published under AGPL v3 on GitHub, fully auditable, with a public warrant canary and documented vulnerability disclosure. Free plan includes 10 GB encrypted storage, 5 aliases, and 1 custom domain. Paid plans start at $2.99/month. Servers located in Germany.

Security and data privacy is a growing concern. Today, both business users and consumers demand more privacy, without adding complexity to their daily tasks. OX Guard was designed specifically with this in mind. This PGP based security add-on for OX App Suite, integrates seamlessly into our existing email app, letting users encrypt and decrypt emails and files easily. There is a growing demand for privacy from users, while at the same time, they are concerned about increased complexity and reduced usability. OX Guard was designed to satisfy these concerns. An easy to use wizard lets users set up OX Guard quickly, with no additional security know-how. After set up users are able to encrypt and decrypt emails and files with just one click, integrating security seamlessly into day-to-day user workflows.