I.6 TLS Profile

33.2203GPPGeneric Authentication Architecture (GAA)Generic Bootstrapping Architecture (GBA)TS

The UE and the BSF shall support TLS according to the TLS profile given in TS 33.310 [19], Annex E. The only difference is that TLS cipher suites without encryption shall not be used.

The certificates shall comply with the requirements for TLS certificates in clause 6.1 of TS 33.310 [19].

Support of certificate revocation and of the related fields in certificates is optional. If supported, the certificate and CRL profiles in clause 6.1 and 6.1a of TS 33.310 [19] should be followed.

NOTE 1: The management of Root Certificates is out of scope of this Technical Specification.

NOTE 2: If no revocation of certificates is deployed, it should be noted, however, that choosing short lifetimes for BSF certificates may considerably reduce the risk, in case BSF certificates may ever be compromised.

I.6.1 void

I.6.2 Authentication of the BSF

The Client shall authenticate the BSF by use of a server certificate. The client shall match the server name as specified in RFC 2818 [18] section 3.1.

The ME shall use a preconfigured list of trusted root certificates for 2G GBA BSF server certificate validation. BSF server certificate validation shall not require manual user interaction.

NOTE: The risk of the UE using the root certificates associated with a compromised Certification Authority (CA) can be greatly reduced when the preconfigured list of trusted root certificates is restricted to a low number of CAs trusted by the operator, as opposed to the list of all root certificates in a browser’s key store.

I.6.3 Authentication of the UE

The BSF shall not request a certificate in a Server Hello Message from the UE. The BSF shall authenticate the UE as specified in clause I.5.2 of this specification.

I.6.4 Set-up of Security parameters

The TLS Handshake Protocol negotiates a session, which is identified by a Session ID. The Client and the BSF shall allow for resuming a session. The lifetime of a Session ID is subject to local policies of the UE and the BSF. A recommended lifetime is five minutes.

NOTE: If the BSF adheres to the recommended lifetime the UE can be certain to be able to resume the TLS session in case of bootstrapping re-negotiation.

Annex J (informative):
Usage of USS with local policy enforcement in BSF

This Annex describes how the local policy enforcement in the BSF is used between the NAF and the BSF to control the key delivery to the NAF.