Verify a contact with a safety number
Make sure nobody is intercepting your conversation by comparing safety numbers, and what key warnings mean.
End-to-end encryption protects a conversation between two keys. Verifying makes sure those keys really belong to you and the person you think you are talking to, so nobody, including a compromised server, can sit in between.
Compare safety numbers
- Open the conversation and select Verify (the 🛡️ shield at the top).
- Compare the safety number with the other person: in person, or over a call where you recognise their voice. A text message is not enough, because that is exactly what an attacker could fake.
- If the numbers match exactly, select Mark as verified. The chat now shows ✓ Verified.
You only need to do this once per contact, unless their key changes.
Warnings you may see
- This may not be the @name you know: the account now uses a different key than before. Nodz never gives a username to someone else, so this can mean someone is trying to impersonate them. Your old chat is closed and kept separate. Only continue after checking with them in another way, and compare safety numbers again.
- The key is not in the public key log: every account key is recorded in a public, tamper-evident log that your device checks. A key that is missing from it is suspicious; compare safety numbers before you trust the chat.
- Guest: someone who joined through your invitation link without a username has no safety number to compare.
See How Nodz works and our security page for how the key log and the encryption work.