3GPP TSG-T3 (USIM) Meeting #8
Bonn, Germany, August 23 - 25, 1999	Tdoc T3-99246 	

3GPP TSG SA WG3 (Security)	TSG S3#5(99)259

Liaison statement

To:	TSGs T3, N1, N2, R3

From:	TSG S3 (Security)

Title:	Response to LS from TSG T3 (S3-99212) on Multiple Authentication Algorithms and Keys

For:	Information

1	Response to LS on Multiple Authentication Algorithms and Keys
In the liaison statement S3-99212 from 3GPP TSG-T3, T3 requested comments from S3 on support for multiple authentication algorithms and keys, and on the impact of such a feature to the USIM and other parts of the network.

The authentication mechanisms under development in S3 do not currently include explicit support for multiple authentication algorithms or keys.  

S3 agrees that an explicit feature to support algorithm and/or key version identification is useful for desaster recovering such as (e.g.) all the authentication keys in the network being disclosed.

S3 will produce a mechanism to support such a feature. It should be noted that such a feature does not necessarily imply, as claimed in the liaison statement, that “in an authentication request from the network, an algorithm indicator and a key indicator would need to be sent”.  There are other possible implementations of such a feature.  For example, consider a one-time provisioning command sent to the USIM that triggers the selection of a new “current” authentication algorithm and/or key.

Any mechanism that provides authentication algorithm or key identification to the mobile would obviously impact the air interface and core network signaling messages.