5 Integrity algorithm GIA4

3GPP55.241GIA4 specificationSpecification of the GIA4 integrity algorithm for General Packet Radio Service (GPRS)TS

5.1 Introduction

The integrity algorithm GIA4 computes a Message Authentication Code (MAC) on an input message under an integrity key IK128. The input message may be between 1 and 65536 octets long.

For ease of implementation the algorithm is based on the same block cipher (KASUMI) as is used by the confidentiality algorithm GEA4.

5.2 Inputs and outputs

The inputs to the algorithm are given in table 5.2.1, the output in table 5.2.2:

Table 5.2.1: GIA4 inputs

Parameter

Size (bits)

Comment

INPUT-I

32

Frame dependent input INPUT-I[0]…INPUT-I[31]

M

The length of MESSAGE in octets (1-65536)

MESSAGE

8M

Input octet stream MESSAGE{0}….MESSAGE{M-1}

DIRECTION

1

Direction of transmission DIRECTION[0]

FRAMETYPE

8

Input value signifying the type of frame to be protected

KI128

128

Integrity key KI128[0]…KI128[127]

Table 5.2.2: GIA4 output

Parameter

Size (bits)

Comment

MAC

32

Message authentication code MAC[0]…MAC[31]

5.3 Components and architecture

This clause only available under licence.
See http://www.etsi.org/about/what-we-do/security-algorithms-and-codes/cellular-algorithm-licences.

5.4 Initialisation

This clause only available under licence.
See http://www.etsi.org/about/what-we-do/security-algorithms-and-codes/cellular-algorithm-licences.

5.5 Calculation

This clause only available under licence.
See http://www.etsi.org/about/what-we-do/security-algorithms-and-codes/cellular-algorithm-licences.

Annex A (informative):
Components and architecture of the GIA4 algorithm

This clause only available under licence.
See http://www.etsi.org/about/what-we-do/security-algorithms-and-codes/cellular-algorithm-licences.

Annex B (informative):
Simulation program listing

This clause only available under licence.
See http://www.etsi.org/about/what-we-do/security-algorithms-and-codes/cellular-algorithm-licences.

Annex C (informative):
Change history

Change history

Date

Meeting

TDoc

CR

Rev

Cat

Subject/Comment

New version

2016-04

SA3#83

–

–

–

First Draft

0.1.0

2016-04

SA3#83

–

–

–

Updated and Shared with French Government

0.2.0

2016-05

SA3#83

–

–

–

Algorithm redacted

0.2.2

2016-04

SA3#85

–

–

–

Full Specification with Example Code

0.3.0

2016-06

SA#72

SP-160377

EditHelp editorial fix and presented for information

1.0.0

2016-11

SA3#85

Sent for Approval with only version changes

1.1.0

2016-11

SA3#85

Changed editors note to reflect availability of the content

1.1.1

2016-11

SA#74

SP-160791

MCC clean up, redacted version for TSG SA approval

2.0.0

2016-12

SA#74

Approved by TSG SA

13.0.0

2017-03

SA#75

–

–

–

Promotion to Release 14 without technical change

14.0.0

2018-06

–

–

–

–

–

Update to Rel-15 version (MCC)

15.0.0

2018-06

Change to GSM logo

15.0.1

2020-07

–

–

–

–

–

Update to Rel-16 version (MCC)

16.0.0

2022-03

–

–

–

–

–

Update to Rel-17 version (MCC)

17.0.0