Series: Signal for Everyone (Not Just Spies)
At some point, Signal will show you a warning: “Safety Number Changed.”
Most people click “OK” and hope for the best. Totally understandable, but here’s what it actually means.
👋 The Secret Handshake Analogy
Imagine you and I agree on a secret handshake. Every time we meet, we use it. If I show up one day and suddenly don’t know the handshake…you’d probably be suspicious.
Signal uses a digital version of this handshake between you and every person you message. The “Safety Number” is basically your handshake code.
🔄 Why It Changes
Most of the time, this warning simply means:
- Your friend got a new phone,
- Reinstalled Signal,
- Or transferred devices.
No big deal.
However, it can rarely mean that someone is trying to intercept or impersonate the conversation.
So how do you know which one it is?
🧪 Try It: How to Check
- Open the chat with your friend.
- Tap their name.
- Tap Safety Number.
- Either compare the numbers manually or scan each other’s QR code in person.
If you scan in person, the chat gets a little “Verified” checkmark. From then on, if anything changes, you’ll know.
🟡 Golden Rule Reminder
Signal protects your message while it travels. It cannot protect it once it arrives.