3GPP TSG SA WG3 (Security) meeting #7	Tdoc S3-99363
Den Haag, 26 - 27 October 1999

Source:	T-Mobil
Title:	Issues for refinement of 33.102
Agenda Item:	11.2

This document describes some issues related AKA and SQN management that need refinement to make 33.102 more transparent.

1.	6.4.4 Key Set Identifier
Who initialized KSI? Which entities exchange KSI? Is KSI equal to CKSN in GSM?

Proposal: 
Adopt GSM approach.
2.	6.4.4 Cipher key and integrity key identification
Numbering not incremented to 6.4.5 (applies also to 6.4.X) !
3.	6.4.5 Integrity Key Lifetime
Which 'counter' should reach a maximum value? 
What is the mechanism defined?

Proposal:
oldHFN		HFN value stored at last key generation (off set)
currentHFN	current HFN
deltaHFN		max. value when new key establishment is needed (to be defined by HE)
			initiate new key generation, if currentHFN - oldHFN = deltaHFN
4.	Annex C: 
a) Is annex C normative/informative? It is proposed to call it normative with an explanation, that at least one of the alternatives described in annex C.1 to C.6 has to be chosen. 
b) It is unusual to describe one alternative in the main body and all other alternatives in an annex even if all these alternatives should be equal good. One can say that by describing an alternative in the main body this one becomes mandatory even if annex C states that all alternatives are equal. 
c) The pointer in the main body to annex C is only embedded in a note. 
d) Are all these alternatives really necessary?
5.	Annex C.1: 
The headline of Annex C.1 talks of "... two individual counters ...", even if exact this text was removed from main body and replaced by "... an individual counter ...".
6.	Annex C.2: 
If SQNs will be derived from the time value clause 6.2.3 'Re-synchronisation procedure' and some parts of clause 6.3.2 can be removed. 

Proposal: Add a pointer in 6.3.8 to annex C and change the appropriate text in annex C note to normal text. 

CR018 talks (in clause 6.3.8) about the possibility that SQNs have not to be concealed. This possibility is indicated in annex C only as a note. 

7.	Annex C.3 and C.4: 
It has to be added that also SQN > SQNMS are acceptable. Up to now this is only defined for the alternative described in the main body (see also annex C.1).
8.	Annex C.6: 
CR is yet missing.
9.	Annex F: 
Structure and coding of AMF not yet defined. 
10.	Annex F.3: 
The parameter MODE is used even if it is not defined anywhere.
11.	Annex C.5: 
SQNmax is not defined.