3 Definitions, symbols, abbreviations and conventions

33.1053G Security3GPPCryptographic algorithm requirementsRelease 17TS

3.1 Definitions

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

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.

3.2 Symbols

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

|| Concatenation

Å Exclusive or

f0 random challenge generating function

f1 network authentication function

f1* the re-synchronisation message authentication function;

f2 user authentication function

f3 cipher key derivation function

f4 integrity key derivation function

f5 anonymity key derivation function for normal operation

f5* anonymity key derivation function for re-synchronisation

f8 UMTS encryption algorithm

f9 UMTS integrity algorithm

3.3 Abbreviations

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

3GPP 3rd Generation Partnership Project

AK Anonymity key

AuC Authentication Centre

AUTN Authentication token

COUNT-C Time variant parameter for synchronisation of ciphering

COUNT-I Time variant parameter for synchronisation of data integrity

CK Cipher key

IK Integrity key

IMSI International Mobile Subscriber Identity

IPR Intellectual Property Right

MAC Medium access control (sublayer of Layer 2 in RAN)

MAC Message authentication code

MAC-A MAC used for authentication and key agreement

MAC-I MAC used for data integrity of signalling messages

PDU Protocol data unit

RAND Random challenge

RES User response

RLC Radio link control (sublayer of Layer 2 in RAN)

RNC Radio network controller

SDU Signalling data unit

SQN Sequence number

UE User equipment

USIM User Services Identity Module

XMAC-A Expected MAC used for authentication and key agreement

XMAC-I Expected MAC used for data integrity of signalling messages

XRES Expected user response

3.4 Conventions

All data variables in this specification are presented with the most significant substring on the left hand side and the least significant substring on the right hand side. A substring may be a bit, byte or other arbitrary length bitstring. Where a variable is broken down into a number of substrings, the leftmost (most significant) substring is numbered 0, the next most significant is numbered 1, and so on through to the least significant.