How to verify a safety number

The one-minute habit that upgrades a pairing from probably-fine to confirmed. Both phones derive the same number from the two keys. If what you see matches what they see, there is no one in the middle.

~1 minute iOS CarrierPony
At a glance
  1. Open the conversation details
  2. Find the safety number
  3. Compare it with your contact
  4. Match: you're verified
  5. Mismatch: stop and re-pair
Prerequisites
  • An existing pairing with your contact
Step 1

Open the conversation details

In the conversation with your contact, open its details. The safety number for this pairing is shown there.

Step 2

Have your contact do the same

On their phone, the same screen shows the same number if the pairing is clean.

Step 3

Compare over a trusted channel

Read the numbers to each other in person, over a voice call, or across any channel an attacker is unlikely to control at the same time as the relay path.

Step 4

Act on the result

Match: the conversation is verified and you can treat the encryption as confirmed. Mismatch: stop, delete the pairing, and pair again, ideally face to face.

Verify it worked

  • You and your contact read the identical number.
  • The app reflects the verified state for the conversation.

Common questions

How often do I need to do this?

Once per pairing. The app pins the keys afterward, and only that exact key will ever verify as your contact. If they start over with a new identity, they'll have to pair with you again, which is your cue to verify the new number.

Why would the numbers not match?

Either someone intercepted the pairing (rare but exactly what this catches), or the two of you are comparing different conversations. Rule out the mundane, then re-pair carefully.

Is verification required to chat?

No. Messaging works immediately after pairing. Verification removes the remaining first-contact risk and is strongly recommended before anything sensitive.

Next steps

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