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How to send secure emails in Gmail with confidential mode and an SMS passcode
Turn on Gmail confidential mode to add an expiry date and an SMS passcode to an email, so only the recipient with the phone can read it. Works for Gmail and non-Gmail recipients.
By Nur Islam- 4:02 video
- 5 steps
- 8.4K views
Jump to a step (5)
When you email contracts, personal details or private files, anyone who can get into the recipient's inbox can read them, and the recipient can forward them anywhere. Most people do not know Gmail has a built-in way to lock that down.
Gmail confidential mode puts the message and its attachments behind Google's servers. You set how long it stays available, and you can require a one-time passcode sent by text to the recipient's phone. Gmail recipients cannot forward the message.
The video sends one email to another Gmail account and one to a Yahoo account, and shows what each recipient sees.
What you need
- A Gmail or Google Workspace account
- The recipient's mobile phone number, for the SMS passcode
Step by step
0 of 5 done-
01
Compose the email
In Gmail, click Compose and maximize the window. Add a subject, the message body and any attachments, then add the recipient.
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02
Turn on confidential mode
In the bottom toolbar of the compose window, click the lock and clock icon, Toggle confidential mode.
Set the expiry. The default is 1 week, and you can choose anything from 1 day to 5 years. After this time the recipient can no longer open the email.
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03
Require an SMS passcode
Under Require passcode, select SMS passcode and click Save. The compose window now shows the date the content expires.
Click Send. Gmail asks for the recipient's phone number. Choose the country code, type the number and send.
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04
Open it as a Gmail recipient
The recipient sees the subject in their inbox. When they open the email, Gmail asks them to confirm their identity. They click Send passcode, enter the code from their phone and click Submit. Then they can read the email and open the attachment.
There is no Forward option. The recipient can still reply.
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05
Send to a non-Gmail address
Compose the same way, turn on confidential mode with an expiry and SMS passcode, and send to an Outlook, Yahoo or other address.
The recipient sees only the subject and a View the email button. It opens in a new tab in Gmail confidential mode, where they request the passcode, enter it and read the message and attachment. The content never sits in their Yahoo inbox. They can forward the notice, but anyone without the phone cannot open it.
Tips and common problems
- Confidential mode needs an expiry date. Pick a time long enough for the recipient to act, up to 5 years.
- The SMS passcode is what stops someone else with access to the recipient's inbox from reading the email. Without it, anyone in that mailbox can open it.
- Confidential mode blocks forwarding in Gmail, but it cannot stop screenshots or someone copying the text by hand.
- Google can still read confidential mode emails. It is access control, not end-to-end encryption. For full encryption, where even the provider cannot read the message, you need a different method.
Questions
Is Gmail confidential mode encrypted?
It protects access with an expiry date and optional SMS passcode, and the email is encrypted in transit like normal Gmail. It is not end-to-end encryption, so Google can still access the content.
Can someone without Gmail open a confidential mode email?
Yes. They get a link that opens the message in Gmail confidential mode in their browser. With an SMS passcode set, they must enter the code sent to their phone.
Can the recipient forward a confidential Gmail email?
Gmail recipients do not get a Forward option. Non-Gmail recipients can forward the notice, but the content still needs the passcode, so it only opens for the person with the phone.
