You want to look at the RSN IE (information element):
Tag: RSN Information
Tag Number: RSN Information (48)
Tag length: 20
RSN Version: 1
Group Cipher Suite: 00:0f:ac (Ieee 802.11) AES (CCM)
Pairwise Cipher Suite Count: 1
Pairwise Cipher Suite List 00:0f:ac (Ieee 802.11) AES (CCM)
Auth Key Management (AKM) Suite Count: 1
Auth Key Management (AKM) List 00:0f:ac (Ieee 802.11) WPA
RSN Capabilities: 0x0028
This will provide some of the information needed: WPA2 supported, Personal (PSK) or Enterprise. This example is WPA2-Enterprise.