Creating AES session key for Cipurse (Java Card)?

Question

I try to get into cipher, mutual authenticate and such and figured it might be good to see what is "on" the market. Now, cipurse states in its specifications a term like this to generate the session key:

k0 = AES (key = PAD2 (kP) XOR PAD (rT), kID) XOR kID

where k0 is the session key, kP is an on-card calculated key, rT is the response from the terminal. PAD stands for padding (leading zeroes), PAD 2 for double padding (leading zeros) and kID is the secret key from the card.

Now as far as I am aware I create a key this way:

    AESKey k0_pre = (AESKey) KeyBuilder.buildKey(KeyBuilder.TYPE_AES_TRANSIENT_DESELECT, KeyBuilder.LENGTH_AES_128, false);
    k0_pre.clearKey();
    k0_pre.setKey(key, (short) 0);

Now the one question I have is concerning just a little comma nameingly

key = PAD2 (kP) XOR PAD (rT), kID

setKey takes a byte[] and an offset, kID is not an offset cleary - should this comma be and "AND" or should those two expressions should be concatenated or something completely different?

The example kID in the guidelines is

53 45 43 5f 4d 45 4d 4f 52 59 20 4b 45 59 20 31

The result after for PAD2 (kP) XOR PAD (rT) is

00 00 00 00 b7 a0 d2 cb 01 15 25 3f c4 0d 43 8f

and the k0_pre is then to be:

72 4b e3 3e 05 47 b5 99 9c 78 13 9d 8b 25 94 e6

I just don't know how this AES Key is generated out of "2" input keys

Answer 1

I found the answer some place else:

The encryption of a 128-bit message block m using a 128-bit key k using the advanced encryption standard AES is denoted by c := AES (key = k, m).

So, for my question the secret key kID is the message block, now it all makes sense!