What is Automatic Key Verification?
Signal is always end-to-end encrypted, and automatic key verification provides an additional, streamlined way to confirm that there's no unexpected party between you and the other "end" of an end-to-end encrypted session.
It is an additional check alongside Signal’s safety numbers. If the feature is available and verification succeeds, you will see a green checkmark and “Encryption verified.”
This does not verify real-world identity and does not prevent impersonation or account compromise.
How do I use it?
- Open the contact’s profile (from a 1:1 chat, group chat, or call log).
- Choose View Safety Number.
- Choose Verify automatically.
If the feature is available and verification is successful, you will see a green checkmark and “Encryption verified.”
When is it available?
Automatic Key Verification is available only when Signal has your contact’s phone number.
For example, this may be the case if:
- you started the chat using “Find by phone number.”
- the contact is saved in your address book and discoverable by phone number.
- the contact has set their phone number to visible.
Why is it not available?
This feature may not be available if:
- you started a chat using a username instead of a phone number.
- the contact is not discoverable by phone number.
- the contact changed their phone number.
- your device has an outdated phone number for the contact.
- your device has incorrect date and time settings for your time zone.
Your messages remain end-to-end encrypted even if Automatic Key Verification is not available.
What should I do instead?
If Automatic Key Verification is not available, use safety numbers to verify your connection.
- Scan a QR code.
- Compare the safety number with your contact.
This is ideally completed in person or through another trusted channel.
Does this affect my privacy?
No. Your messages remain end-to-end encrypted.
This feature only helps confirm that you and your contact are using the correct encryption keys. A missing or changing verification status does not indicate a compromised chat.
Reminder: It does not verify the real-world identity of the person using that account. Someone can still pretend to be another person, brand, or service.
Why can availability change?
Automatic key verification may stop being available in some situations, such as if your contact changes their phone number in Signal. In that case, we recommend falling back to verifying safety numbers manually, ideally in person or through another trusted channel.
If you think Automatic Key Verification should be available but isn’t:
- Confirm that one of the supported phone number conditions applies.
- Make sure all devices are updated to the latest version of Signal.
- Android v8.21.6 or later.
- iOS v8.22.0 or later.
- Desktop v8.21.0 or later.
- Contact us from the in-app steps. Open Signal on your phone, go to Signal Settings (profile) and then contact us.
- Make sure to include a debug log and let us know whether anyone recently changed phone numbers, switched devices, or reinstalled Signal.
Learn more
Automatic Key Verification is based on key transparency, which helps ensure that Signal devices agree on which encryption keys belong to which phone numbers.
For more technical details, see Signal’s documentation on key transparency.