Question

In the NFC Handover Spec is a sample – how to write WPC Config to a WIFI-Tag.

There is a record-entry for encryption.

So if I want to store Encryption for a WIFI-Config there are 2 points I’m interested to:
TKIP, CCMP

I can store this information, but I don’t know by reading this information if this refers to
GroupCipher OR PairwiseCipher OR both?

So I can set this:

config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);
config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);

and

config.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
config.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);

But when do I set TKIP, CCMP for Pairwise AND/ OR GroupCipher.

Do I always set both? Also if I don’t know if the encrpytion on the tag refers to Group or Pairwise?

I hope you know what I mean, If i read now AES from the tag, do I set

config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);

OR

config.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);

OR

config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
config.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);

Answer 1

If you want to connect to WPA(1) AP then you have to use TKIP. For a WPA2 AP you need CCMP.

Now if you want to use both (WPA(1) and WPA2 AP) then you have to set both.

You should use same mechanism (TKIP/CCMP) for both PairWise & GroupWise Keys.

Pairwise Cipher key is used for unicast messages, while GroupCipher key is used for broadcast.

Hope this helps,