Mimecast Secure Messaging

Mimecast Secure Messaging helps organizations protect sensitive information sent by email, including financial records and customer data. Protected messages are delivered through a secure web portal, and Mimecast says that information remains in its cloud. Senders can set read receipts and expiration dates, and restrict printing or replies. Messages and attachments are scanned for viruses, checked against data leak prevention policies, and stored in an AES-encrypted archive. Recipients use portal instructions to retrieve messages, download attachments, and reply securely. Email security gateway policies can initiate Secure Messaging, and administrator-defined criteria can trigger encryption for Office 365 email when TLS is unavailable. Mimecast says users do not need additional software downloads or hardware. The service is listed for Android, iOS, macOS, web, and Windows, with Outlook integration and administrative access controls. Portal access is available to customers with Mimecast end-user applications, and the portal is included only in service packages that already include those applications. Pricing is on request.

Mimecast Secure Messaging adds portal delivery and sender controls for sensitive email, with policy-triggered options and scanning described by the maker. Organizations should confirm that their service package includes the End User Portal and request pricing.

Secure Messaging suits organizations sending sensitive information to colleagues or partners by email. It may be relevant where administrators want policy-triggered protection and controlled recipient access through a portal.

Mimecast Secure Messaging is a business email security service that moves sensitive correspondence into a protected web portal. It is best for organizations sharing regulated or confidential information with employees and partners, particularly those already operating Mimecast’s email gateway. Its main advantage is policy-controlled delivery and recipient actions; custom pricing and package-dependent portal access make it a poor fit for individuals seeking a self-serve tool.

Overview

Instead of putting protected content directly in a conventional inbox, Secure Messaging sends recipients instructions to sign in to Mimecast’s cloud portal. There they can read the message, download attachments, and reply securely. Mimecast says sensitive information never leaves its cloud, which gives businesses a consistent route for financial records, customer data, and other confidential material. The trade-off is that recipients must use the portal rather than simply opening the complete message in their usual mail application.

The service is part of Mimecast’s business email subscription offering and supports communication with colleagues and outside partners. Neither senders nor recipients need additional software downloads or dedicated hardware.

Key features

Sender and administrator controls

Before sending, users can request read receipts, set an expiration date, and restrict printing or replying. These controls are useful when access should be time-limited or when a message must not be casually reproduced. They also add friction: recipients may be unable to print or respond unless the sender explicitly permits it.

Administrators can trigger secure delivery automatically when an email matches policies at the email security gateway. For Office 365, Mimecast says encryption can apply when TLS is unavailable or when administrator-defined conditions match a recipient, domain, or subject keyword. That policy approach suits organizations that need consistent enforcement instead of relying on every employee to choose encryption correctly.

Scanning and storage

Mimecast says messages and attachments are scanned for viruses, evaluated against data-leak-prevention policies, and stored in an AES-encrypted archive. This combination connects secure delivery with malware and information-governance checks, making it more suitable for managed business environments than ad hoc encrypted-mail services.

Portal access

The browser-based End User Portal is available across Windows, macOS, iOS, Android, and ChromeOS with current Chrome, Edge, Firefox, or Safari browsers. Outlook integration is supported, and administrative access controls are included. The portal beta is open to customers with Mimecast end-user applications, but it is included only in service packages that already contain those applications. Organizations should verify entitlement before treating portal access as part of a purchase.

Pricing

Mimecast uses paid, custom pricing rather than published self-serve rates. The Critical plan combines secure messaging and large-file sending with AI-powered email security and email continuity. It is the broadest fit for organizations that want those capabilities together, but the lack of a posted price means budgeting requires a sales discussion.

Advanced includes secure messaging and large-file sending, email security with data protection, and email continuity. Choose it when data protection is more important than the Critical plan’s AI-focused security scope. Premium adds comprehensive protection across collaboration tools alongside secure messaging, large-file sending, and email continuity, making it the logical option for businesses protecting more than email. All three plans require a quote, and portal availability depends on the underlying service package.

Platforms

Secure Messaging works through the web portal on Windows, macOS, iOS, Android, and ChromeOS using current Chrome, Edge, Firefox, or Safari browsers. Outlook integration supports existing email workflows, while recipients can use a browser without installing client software.

Who it's for

This is aimed at organizations exchanging sensitive records with colleagues and partners, especially those that already use Mimecast’s business email gateway or end-user applications. Policy-triggered encryption, expiry, recipient restrictions, scanning, and administrative controls are valuable where compliance and repeatable enforcement matter. It is not a natural choice for a lone user or small team wanting transparent pricing, a free tier, or a lightweight consumer mailbox add-on.

Pros and cons

• Pro: Portal delivery keeps protected content in Mimecast’s cloud instead of ordinary email.
• Pro: Gateway policies can automate encryption based on recipients, domains, keywords, or TLS availability.
• Pro: Expiration, read receipts, and print/reply restrictions give senders concrete control over use.
• Pro: Virus scanning, data-leak-prevention checks, and AES-encrypted archiving add managed protection.
• Con: Recipients must authenticate through a portal, which is less immediate than normal inbox reading.
• Con: Portal access is tied to qualifying Mimecast packages rather than guaranteed as a standalone purchase.
• Con: Every plan uses custom pricing, so comparisons and small-team budgeting are difficult.

Alternatives

Browse Email Encryption Software or File encryption tools for broader category comparisons. Choose Send It Secure instead if you want a freemium option with a free Guest plan, 30-day retention, 25 MB files, and ten lifetime sends to non-paid users. SecureMyEmail is better for individuals wanting a free one-address plan or a consumer-oriented multi-platform app. Pick DataMotion Secure Email Exchange when a freemium offering and enterprise sales model are preferable. Proofpoint Email DLP and Encryption is an alternative paid service without a free plan. Microsoft Exchange Online suits organizations seeking a broader hosted-mail platform with published mailbox and message-size allowances on Plan 1. Virtru Email Encryption offers paid Starter and Business plans at $119 and $219 per month billed annually for five users. c.Email is a free extension with unlimited email addresses. FlowCrypt is worth considering when a free extension tier for fewer than 100 users and 5 MB attachments is sufficient.

Verdict

Choose Mimecast Secure Messaging if your organization needs portal-based protection governed by email policies, with sender restrictions, scanning, archiving, and Office 365 conditions in one business subscription. Look elsewhere if you need transparent rates, a free plan, or a recipient experience that stays entirely inside the ordinary inbox.