The Best Secure Email Services to Protect Your Business Data

Email is one of the most widely used communication methods in business, but without robust protections, every message could be a target for cyber attack or data breach.

Thankfully, there’s a wide range of secure email services available to help your organisation protect sensitive information and maintain privacy.

We’ve assessed the most widely used secure email providers based on their encryption methods, authentication options, usability, and pricing.

What Is a Secure Email Service?

A secure email service adds multiple layers of protection to standard email, offering safeguards like encryption, identity authentication, audit trails, and message revoke features.

The goal is to reduce the risk of email-based threats such as interception, data loss, or misdelivery while helping businesses stay compliant.

Why Do You Need a Secure Email Service?

Email was never designed to be a secure channel. Yet today, it underpins most business communications.

With the rise in remote work and cloud platforms, threats are increasing. 32% of UK businesses reported a cyber attack or breach in 2022-2023. Phishing attacks accounted for 83% of those incidents.

And it's not just malicious attacks. Misdirected emails remain a leading cause of breaches.

88% of all breaches can be traced back to human error.

Types of Secure Email Service

Different providers specialise in different threat vectors. Some offer protection from inbound threats, others focus on outbound security.

• Outbound email security protects sensitive data leaving your organisation, helping prevent unauthorised access.
• Inbound email security scans incoming messages for threats and ensures encryption until opened by the intended recipient.

Large organisations might opt for a secure email gateway to enforce policies at the server level.

Smaller firms may prefer desktop-based software to apply protections on an individual user basis.

Choosing a Secure Email Service

Look for these key features when evaluating your options:

• Strong encryption - such as AES-256 (Advanced Encryption Standard), widely trusted across industries.
• Recipient authentication - verify that only the right person can open the message.
• Email recall - revoke access if you send something in error.
• Audit trails - track message access and prove compliance.

Best Secure Email Services

There’s no one-size-fits-all. From Microsoft’s Purview to Mailock’s user-friendly encryption, each service offers a different mix of protections and experiences.

Mailock Secure Email

Mailock is a dedicated outbound email solution that secures sensitive customer information using your existing email setup.

Available as a desktop app or an enterprise gateway, it’s suitable for organisations of all sizes.

Features include:

• End-to-end AES-256 encryption, with unlimited secure replies for recipients.
• Recipient authentication via SMS, Q&A, Unipass ID, or email verification.
• Message revoke for sent messages and attachments.
• Read notifications for open status updates.
• Audit trails including read, open, and revoke status logs.
• Trigger words that prompt secure sending based on message content.

Key considerations: Recipients can read Mailock emails without an account. A free account is required to reply (with limited secure sends). Includes an Outlook Add-in for easy use.

Learn more about Mailock.

Microsoft Purview Message Encryption (MPME)

Microsoft Purview Message Encryption (formerly Office Message Encryption) is included with Microsoft 365 E5 and other enterprise packages.

Features include:

• AES-256 encryption, with encrypted replies.
• Message recall (limited, requires PowerShell configuration).
• Inbox access verification via Microsoft or Google login, or one-time codes.
• Read receipts, configurable by sender and recipient.
• Audit dashboard showing timestamps, recipients, and access status.

Key considerations: No recipient authentication or trigger word support. Setup may require assistance from a Microsoft specialist to configure Azure Information Rights Management.

Read our full review of Microsoft’s secure email.

Egress Cloud Email Security Suite

Egress combines email protection tools into one suite, with Defend, Prevent, and Protect modules to guard against inbound and outbound threats.

Features include:

• AES-256 encryption, applied by users or admins.
• Access privileges such as restrictions on forwarding or downloading.
• Q&A recipient authentication options.
• Machine learning prompts for secure sending.
• Microsoft 365 integration with Outlook add-in.

Key considerations: Recipients must create a free account for replies (25 credits per month, 1 per recipient).

Compare Egress vs Mailock.

Zivver Secure Email

Zivver helps reduce the risk of outbound errors, with machine learning tools and secure file transfers up to 5TB.

Features include:

• RSA 2048 encryption for messages and attachments.
• Access code and SMS authentication.
• Secure file transfer (large file sizes).
• Email expiration and recall features.
• Contextual correction using AI prompts.

Key considerations: Zivver offers an Outlook add-in and Chrome extension. Some features vary by licence tier.

Read our Zivver vs Mailock guide.

Mimecast Secure Email Messaging

Mimecast is best suited to enterprises needing high-scale email security and continuity.

Features include:

• AES-256 encryption based on rules or manual triggers.
• Message expiration and recall options.
• Two-factor authentication for users.
• Read notifications for senders.
• Custom branding for outbound secure messages.

Key considerations: Reviews cite a complex interface and limited support. Pricing is typically geared towards firms with 100+ users.

See how Mimecast compares to Mailock.

Proofpoint Email Encryption

Proofpoint is a compliance-focused provider with robust admin controls and policy-based encryption settings.

Features include:

• AES-256 encryption configured through content rules.
• Message revoke at admin level.
• Integration with Outlook and Gmail.

Key considerations: Recipients must create a Proofpoint account to view secure messages.

There’s no recipient authentication. Messages expire after 15 days.

Explore our Proofpoint vs Mailock comparison.

The Best Secure Email?

Email isn’t going anywhere - but the way we secure it must evolve.

Each provider offers a unique mix of protections.

For many businesses, Mailock strikes the right balance between security, usability, and compliance, whether you’re a sole trader or a large enterprise.

Try Mailock to protect your customer data with secure, seamless encrypted email.

References

The Latest Cyber Crime Statistics, AAG IT, 2023

88 Percent of Data Breaches Are Caused by Human Error, KnowBe4, 2023

Reviewed by

Sabrina McClune, 07.06.24

Sam Kendall, 13.06.25