I was helping a person with his computer today, and he was convinced that his router's WPA key was 7 characters (with some brand of consumer router). He has been able to connect with this on a number of computers, but when stepping him through it with Ubuntu we found that Network Manager imposes a strict limit of 8 or more characters.
Before I fire off a bug report, I would like to know: is that 8 or more character limit a hard, technical limit (and the guy on the phone just crazy), or is it indeed possible to have a WPA key with 7 characters?
Best Answer
WPA Pre-shared key (PSK) mode, defined in IEEE 802.11i-2004, uses PBKDF2 as described in PKCS #5. While PBKDF2 has no minimum length, the IEEE standard states in H.4 Suggested pass-phrase-to-PSK mapping (which includes a discussion of security considerations):
UPDATE: A thought occurs -- note that this is based on ASCII characters. Perhaps your 7-character WPA PSK has trailing whitespace!