Comment Re:if that's true, (Score 4, Informative) 487
I was curious about this too. But the AC below gave a nice hint, so I went looking for a better explanation. Here is the blurb from the Wiki,
Also referred to as WPA-PSK (Pre-shared key) mode, this is designed for home and small office networks and doesn't require an authentication server.[9] Each wireless network device encrypts the network traffic using a 256 bit key. This key may be entered either as a string of 64 hexadecimal digits, or as a passphrase of 8 to 63 printable ASCII characters.[10] If ASCII characters are used, the 256 bit key is calculated by applying the PBKDF2 key derivation function to the passphrase, using the SSID as the salt and 4096 iterations of HMAC-SHA1.[11] WPA-Personal mode is available with both WPA and WPA2.
So it seems the PSK can be passed around without revealing the passphrase. But if I also remember correctly, the PSK is supposed to rotate (or maybe that's WPA2).