I'm trying to figure out a good John The Ripper rule for WPA2 that won't waste time testing impossible passwords. Thus the question - are there any limits on what's allowed in a WPA2 password? Can it be any binary string or are we limited to ASCII or a particular encoding? Is its length any limited? I remember that there's a minimum password length limit.
According to the 802.11i-2004 specification (link to download 802.11i-2004 pdf):
A pass-phrase is a sequence of between 8 and 63 ASCII-encoded characters. The limit of 63 comes from the desire to distinguish between a pass-phrase and a PSK displayed as 64 hexadecimal characters.