How does this work from a security perspective? Given the lack of apparent entropy can’t a malicious actor conceivably enter the correct phrase before the good actor?
“An important property is that an eavesdropper or man-in-the-middle cannot obtain enough information to be able to brute-force guess a password without further interactions with the parties for each (few) guesses. This means that strong security can be obtained using weak passwords.”
https://github.com/magic-wormhole/magic-wormhole/blob/master... has a larger writeup.
That is as opposed to sending a public key or key fingerprint. In that case there would be little value to the attacker in seeing the transfer. They would have to MITM the transfer of the key itself. If you wanted to prevent the attacker from sending bogus files you would also have to transfer some sort of signing key.
So a short, time limited, secret vs a longer public value.