trying to use SHA256 on hostapd

[David]

Hi all;

Using hostapd 0.6.8 with madwifi-0.9.4, linux kernel 2.6.18 (old but
works...), on an AR5212 802.11 b/g card,
using wpa-psk mode w/ccmp (aes), known as "WPA2"

in hostapd.conf using the line
wpa_key_mgmt=WPA-PSK      everything works


but trying to use SHA-256 like this
wpa_key_mgmt=WPA-PSK-SHA256       produces errors when I start hostap

Line xxx: invalid key_mgmt 'WPA-PSK-SHA256'
1 errors found in configuration file '/etc/hostapd.conf'

       [ !! ]

I get the exact same results (working and non-working) on other versions
of hostap.  Reading the sample config file does not clarify; how do I
enable this?

Thanks,
David


============= my hostapd.conf: ==================
interface=ath0
bridge=br0
driver=madwifi
logger_syslog=-1
logger_syslog_level=0
logger_stdout=-1
logger_stdout_level=0
debug=4
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=nowireshere
macaddr_acl=0
auth_algs=3
ieee8021x=0
own_ip_addr=127.0.0.1
wpa=2
wpa_passphrase=wouldntyouliketoknow

wpa_key_mgmt=WPA-PSK-SHA256

wpa_pairwise=CCMP
wpa_group_rekey=86400