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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 on servers without proper protection.

Some email encryption gateways are hosted on-premise and fully managed by internal company administrators. Other gateway solution providers offer a managed service run on cloud-based technology.

Inbound vs. Outbound

Man emailing securely at work

Email encryption gateways have two main functions:

Outbound email encryption encrypts sensitive emails on delivery.

Outbound encryption gateways are a powerful tool for encrypting your communications 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 plays a couple of roles. It:

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

In many cases, organisations will configure a gateway to only allow encrypted emails from certain senders using a domain 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 deploy email encryption gateway software on their server or their providers'. 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 depending on a business’ needs. 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.

Does Microsoft 365 have 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".

How To Get Started

The benefits of email encryption gateways are clear, but there are a lot of things to consider. 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 July 27, 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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