How to send an encrypted email in Gmail

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Gmail uses standard encryption (TLS) to protect your messages by default. We explain how to use enhanced encryption (S/MIME) in Gmail and the best alternative if you’re looking for genuine privacy.

If you have a free email account from a big provider like Gmail, Outlook, or Yahoo Mail, it’s no secret that your messages aren’t private. The only way to truly secure your emails is by using end-to-end encryption (E2EE). That way, only you and the recipient of your messages can read them.

Gmail doesn’t offer E2EE for any of its services. But you can enable stronger encryption to send more secure Gmail messages if you have an eligible paid Google account.

What is email encryption?
How is Gmail encrypted?
How to use Gmail confidential mode
How to send a secure email in Gmail (S/MIME)
Best way to send an encrypted email

What is email encryption?

Email encryption is a process that encodes a message so that only the intended recipient of the message can read it. The email is encrypted (encoded) into an illegible string of characters. The only way to read it is to decrypt (decode) it into its original, readable format using a unique encryption key.

Most major email providers encrypt emails in two ways:

Learn more about how email encryption works

How is Gmail encrypted?

Gmail uses TLS to encrypt emails by default. That means your messages are secure while in transit, as long as the recipient’s email service supports TLS. But once they arrive, the privacy of your emails depends on what encryption the receiving server uses.

Gmail also holds the encryption keys to your messages. So it can access them and hand over their contents to third parties, like advertisers or governments. Google says it no longer scans emails for advertising purposes but does scan messages to enable smart features by default, though you can switch this off.

Gmail offers two other security features for individual messages:

  • Confidential mode — limits options for accessing or sharing a message but doesn’t add stronger encryption
  • S/MIME encryption — stronger encryption that you can enable only with certain paid Google accounts

How to use Gmail confidential mode

Gmail says confidential mode is a way to protect sensitive emails from unauthorized or accidental sharing. With confidential mode, you can: 

  • Set an expiration date for a message and revoke access to it later
  • Remove options to forward, copy, print, or download messages or attachments
  • Require that a verification code (password) be sent by SMS so the recipient has to enter the code to open it

To use confidential mode, click on the icon below in Gmail’s composer window:

Gmail composer window showing the confidential mode icon

Despite its name, confidential mode does little to enhance the security and privacy of your messages:

  • When you set an expiration date and messages “expire”, they’re still stored in your Sent folder, so they remain accessible to Google.
  • While there are no options to forward, copy, print, or download a message, anyone can easily screenshot it.
  • If you want to send a verification code by SMS, you have to give Google the recipient’s phone number.
  • Messages aren’t end-to-end encrypted, so Google can still access them.

Learn more about why Gmail confidential mode isn’t secure or private

How to send a secure email in Gmail (S/MIME)

If you want to use enhanced encryption with Gmail, you can enable S/MIME encryption if you have an eligible paid Google Enterprise or Education account.

S/MIME (short for Secure/Multipurpose Internet Mail Extensions) allows you to encrypt emails with user-specific keys so that only the intended recipients can decrypt them.

To set up S/MIME, log in to your Gmail administrator account, enable hosted S/MIME, and then reload Gmail. You’ll then need to upload a personal authentication certificate from a trusted certificate authority.

While Gmail’s implementation of S/MIME offers stronger encryption, it has several drawbacks:

  • S/MIME isn’t available by default. You need to get an eligible paid account and have an administrator enable it.
  • It only works if the recipient of the email also has S/MIME enabled. There’s no way to send a private email to anyone using a regular Gmail account or any other provider without S/MIME support.
  • Unlike PGP, S/MIME has a centralized system of certificate authorities that could be compromised, though this may only matter to you if you’re at high risk of surveillance.
  • Messages aren’t end-to-end encrypted, so Google can still scan your emails.

Best way to send an encrypted email

If you want to be sure that no one but you and the intended recipient of your email can read it, you need to use end-to-end encryption (E2EE). 

Google said it was developing a Gmail plugin for E2EE in 2014, but it’s yet to materialize. You can enable E2EE in Gmail using a third-party plugin, like Mailvelope, although that requires some technical knowledge.

The easiest way to send a truly secure email is to use Proton Mail, which offers the following and more out of the box:

  • OpenPGP E2EE: Any message you send to someone on Proton Mail is end-to-end encrypted by default or you can send an end-to-end encrypted message using PGP. No one except you and your intended recipient(s) can read them.
  • Password-protected Emails: Easily send an end-to-end encrypted email to anyone who isn’t on Proton Mail without any technical knowledge.
  • Zero-access encryption: No one can access any of your stored emails without your authorization, not even Proton.
  • Open-source transparency: All Proton apps are open source and independently audited, so anyone can verify that they’re secure.
  • Proton Easy Switch: Transfer and encrypt all your emails and contacts from Gmail to Proton Mail in a few clicks — a simple and secure way to test how encrypted email can work for you.

At Proton, our vision is to make secure email available to everyone, so join us and send an encrypted email for free. If you’d like to support our vision, sign up for a paid plan.

Together, we can build a better internet where privacy is the default.

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