Need to Know Airport WiFI encryption

Hi,

When used the latest Core WLAN API, using CWNetworkl class and "securityMode" method to find the WiFi connection details, I am getting a NSNumber equalent to "WPA Personal".
The problem is even if I am connected to network WPA - PSK - TKIP or network using WPA - PSK - AES
the mac is retruning "WPA Personal" only. In short I am not able to find the correct encryption used for the current connection. Any inputs in this regard will be helpful for all here.

Regards,
Pappan