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What Is An Email Encryption Gateway? (Definition & Explainer)

Posted by Picture of Sam Kendall Sam Kendall

An email encryption gateway is an essential tool for securing a business’ enterprise email communications. It makes sure that any sensitive information contained in email messages is protected from unauthorised access by encrypting it before it is sent to external recipients.

Email encryption gateways are a key component of an outbound email security strategy.

They are used to encrypt emails between your organisation and external parties, protecting the confidentiality and integrity of message content as it passes over unencrypted channels.

As well as email security, encryption gateways are used for compliance with data security regulations, ensuring sensitive information isn't leaked during transmission or stored without appropriate protection.

Some email encryption gateways are hosted on-premise and managed by internal company administrators.

Other gateway solution providers offer a fully managed service run on cloud-based technology.

Email encryption gateways should integrate with existing email systems, enhancing security without disrupting everyday email usage.

They're adaptable to various email platforms, maintaining user experience while adding a layer of protection.

These gateways should include strong encryption protocols and recipient verification processes, ensuring that sensitive information remains confidential while accessible to intended recipients.

Inbound vs. Outbound

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Email encryption gateways can play two different functions:

Outbound email encryption gateways encrypt your communications on delivery, with anyone outside your security infrastructure.

This can include customers, partners, vendors, or staff working remotely.

When you send an email to someone outside your company infrastructure, only the intended recipient of that email should be able to decrypt it.

This protects sensitive information from falling into the wrong hands.

Inbound email encryption gateways can:

  • keep incoming encrypted emails secure, making sure they stay protected until the intended recipient needs to gain access.
  • decrypt incoming encrypted emails so that the intended recipients can read them and download any attachments.

In many cases, organisations will configure their inbound email encryption gateway to only allow emails from certain senders using a whitelist.

This gives administrators control over the emails that enter their company's infrastructure and helps to reduce email phishing.

On-Premise vs. Cloud

Man using email encryption gateway at work

Companies can choose to host email encryption gateway software on their server or their gateway vendors' server.

If a company chooses to host their own gateway, the data will usually be stored on-premise, whereas a managed service stores data in a cloud installation administered by the provider.

There are benefits to both deployment types:

  • On-premise deployments give an organisation full control over its infrastructure, which they may need due to regulatory requirements.
  • Cloud deployments offer scalability, efficiency, and ongoing support.

Regardless of the deployment type (on-premise or cloud), most gateway vendors offer or support integrations with major mail exchange servers including Exchange, Office 365, G Suite, and IBM Domino.

If you choose the right email encryption gateway, it should be able to handle high volumes of emails without sacrificing performance, making it suitable for businesses as they grow their customer base.

Does Microsoft 365 Provide An Email Encryption Gateway?

Microsoft 365 does not offer an email encryption gateway as such, though it is able to encrypt outbound and decrypt inbound encrypted messages in a limited sense.

Emails encrypted using M365's native email encryption, Microsoft Purview Message Encryption (MPME), can be decrypted into the inboxes of Microsoft Outlook users.

Some emails can be encrypted by M365 users on enterprise plans, though functionality is limited.

Microsoft's encryption algorithm has also been questioned, leading the company to make a statement that its email encryption should "not be used as a security boundary".

Learn more about Microsoft 365 email encryption.

Getting Started

At Beyond Encryption, our team supports you to deploy our email encryption gateway, Mailock, every step of the way.

We offer both on-premise and cloud installation options, and you’ll benefit from the multi-factor authentication features that make Mailock the solution of choice in the UK financial services industry.

If you're unsure about which type of email encryption gateway is right for you, book a call with our technical team for a consultation.

Further Reading


Originally posted on 15 11 22
Last updated on December 21, 2023

Posted by: Sam Kendall

Sam Kendall is an expert researcher, editor, and marketing specialist. He has worked with B2B brands for almost a decade helping them to refine their digital strategy and streamline ground-level implementation. Sam is passionate about new developments in user experience, demand generation marketing, and customer communications.

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