3 Definitions, symbols and abbreviations

33.2033G Security3GPPAccess security for IP-based servicesTS

3.1 Definitions

For the purposes of the present document, the following terms and definitions apply.

Authenticated (re-) registration: A registration i.e. a SIP register is sent towards the Home Network which will trigger a authentication of the IMS subscriber i.e. a challenge is generated and sent to the UE.

Authentication vector: A quintet (as defined in TS 33.102 [1]) or an SD-AV.

Confidentiality: The property that information is not made available or disclosed to unauthorised individuals, entities or processes.

Data integrity: The property that data has not been altered in an unauthorised manner.

Data origin authentication: The corroboration that the source of data received is as claimed.

Entity authentication: The provision of assurance of the claimed identity of an entity.

Key freshness: A key is fresh if it can be guaranteed to be new, as opposed to an old key being reused through actions of either an adversary or authorised party.

IMS Credentials (IMC): This is defined in TS 21.905 [7].

ISIM – IM Subscriber Identity Module: For the purposes of the present document the ISIM is a term that indicates the collection of IMS security data and functions on a UICC. The ISIM may be a distinct application on the UICC.

NOTE: The distinction between the terms “ISIM” and “ISIM application” is useful for the purpose of describing the IMS security architecture. However, in other 3GPP specifications these terms are used as synonyms, i.e. the term “ISIM” always refers to the ISIM application in the UICC, as defined in TS 31.103 [51].

Security Domain: Networks that are managed by a single administrative authority. Within a security domain the same level of security and usage of security services will be typical.

SIP Digest authentication vector (SD-AV) : Temporary authentication data that enables the IMS network to engage in SIP Digest with a particular user. An SD-AV consists of four elements: a) protection space user hint realm, b) the authentication algorithm, c) the quality of protection value qop and d) the hash of IMPI, realm and password H(A1).

3.2 Symbols

For the purposes of the present document, the following symbols apply:

Cx Reference point between a CSCF and an HSS.

Gi Reference point between GPRS and an external packet data network

Gm Reference point between a UE and a P‑CSCF

Za Reference point between SEGs belonging to different networks/security domains

Zb Reference point between SEGs and NEs or between NEs within the same network/security domain

3.3 Abbreviations

For the purposes of the present document, the following abbreviations apply, TS 21.905 [7] contains additional applicable abbreviations:

AAA Authentication Authorisation Accounting

AKA Authentication and Key Agreement

APN Access Point Name

AS Application Server

AV Authentication Vector

CLF Connectivity Session and Repository Location Function

CSCF Call Session Control Function

ESP Encapsulating Security Payload

GIBA GPRS-IMS-Bundled Authentication

GGSN Gateway GPRS Support Node

HN Home Network

HSS Home Subscriber Server

IBCF Interconnection Border Control Function

I-CSCF Interrogating CSCF

IKE Internet Key Exchange

IM IP Multimedia

IMC IM Credentials

IMPI IM Private Identity

IMPU IM Public Identity

IMS IP Multimedia Core Network Subsystem

IPsec Internet Protocol Security

ISIM IM Services Identity Module

MAC Message Authentication Code

ME Mobile Equipment

NAPT Network Address and Port Translation

NASS Network Access Sub-S ystem

NAT Network Address Translation

NDS Network Domain Security

P-CSCF Proxy-CSCF

R-UIM Removable User Identity Module

S-CSCF Serving-CSCF

SA Security Association

SEG Security Gateway

SD-AV SIP Digest Authentication Vector

SDP Session Description Protocol

SIP Session Initiation Protocol

TLS Transport Layer Security

TNA Trusted Node Authentication

UA User Agent