When optional AES protection is enabled, both sides can see a short “fingerprint” derived locally from the same passphrase.
What it is (and isn’t)
This is a practical typo check. It helps you notice a wrong key early, before you waste time transferring.
It is not, by itself, proof against every network threat. Treat it as a safety signal you can verify out-of-band.
When to use it
Use it whenever you turn on AES-256-GCM for sensitive files, or when you’re on a new network and want an extra sanity check.
If the emoji don’t match
Don’t proceed. Re-enter the passphrase carefully (watch for spaces, keyboard layout, and auto-correct). If it still doesn’t match, reset the session and try again.
Good practice
Pair this with session limits (time / receive count) and Security Burn™ to reduce online guessing during a live transfer.