TSG-T3 (USIM) meeting #4		Tdoc T3-99126
Tokyo 19th - 21st April, 1999

Source: 	S3.03 rapporteur (Bark Vinck, Bart.Vinck@ntnet.atea.be)
Subject: 	3G Security architecture (S3.03, v0.2.0)

Document T3-99127 contains S3.03 version 0.2.0 of the security architecture spec that was sent out to the security group on Monday 19 April, 1999. We (TSG SA3) will agree on a version 0.2.1 by Wednesday afternoon. That will also go to the SA plenary - it should  not be very different from V0.2.0.
SA3 would any feedback that T3 can provide from a review of the document. Issues of particular interst to T3 should be found in the following clauses:
6.2	Enhanced user identity confidentiality
	Instead of the IMUI, the HE may require that the USIM sends out and encrypted IMUI instead. An example mechanism is included in Annex B.

6.3	Authentication and key agreement
	The new authentication mechanism (working assumption) requires that the USIM verifies the data integrity of the received authentication token and challenge, and verifies the freshness of the sequence number. The USIM is also required to keep track of two counters. In addition it should support for the parameters in the re-synchronisation message.

6.4	Data Integrity
	We thank T3 for their LS. Allocation to the USIM or the ME is still an open issue. The data integrity function required for this purpose is different from the one required for authentication and key agreement.

8.1	User-USIM authentication
	This text is based on GSM 11.11. But is it O.K.? 

8.2	USIM-Terminal lock
	This text is NOT based on GSM 02.22 (because the contributor was unaware of the existence of GSM 02.22). Maybe it would be better to replace this text by a summary of GSM 02.22?
	
9.1	SIM Application Toolkit for UMTS

Annex B:	Enhanced user identity confidentiality
	An example mechanism that uses group keys.

Annex C:	Management of sequence numbers
	Mechanisms 3 and 4 involve more memory on the USIM. Their advantages are questionable.

Annex D:	IS-41 evolved authentication scheme
	Backup mechanism for AKA.