To protect your emails, Gmail encrypts them during transfer with transport-layer security (TLS), and you can often check their security. Learn about TLS.
If you use a work or school account, additional encryption types may be available. Learn about email encryption in Gmail.
Check encryption of received emails
Important: On your iPhone or iPad, you can only check the encryption type for emails you receive.
- On your iPhone or iPad, open the Gmail app
.
- At the top, next to the recipient, tap Show details
.
- Check the encryption type:
- Standard encryption (TLS)
- Enhanced encryption (S/MIME)
- No encryption supported
.What to do if an email isn’t encrypted
- If the recipient’s email service doesn’t support the same encryption types as Gmail, you may get a warning message or a red lock icon
. Remove unencrypted addresses or private details before you send.
- If you receive an unencrypted email with sensitive data, inform the sender.
- If you use S/MIME, emails are encrypted whenever possible. You need a valid S/MIME certificate from a trusted source to sign or get S/MIME emails.
Learn why emails aren’t encrypted
For standard encryption to work, the email providers of both the sender and the recipient always have to use TLS.
The email doesn’t support encryptionSome email providers can send encrypted emails to Gmail but not receive them.
If you reply to these messages from Gmail, the red lock icon 
You may get a warning even when your email is encrypted when:
- Past providers have encryption issues.
- Gmail isn't directly sending the message. For example, if you've set up a custom domain name like
[email protected], the red lock icon