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TS 55.242
Specification of the
GIA4 Encryption Algorithms for GPRS –
Implementers' Test Data

3GPP‑Page   ETSI‑search   CONTENT↓
V18.0.0 (PDF)  2024/03  10 p.
V17.0.0  2022/03  10 p.
V16.0.0  2020/06  10 p.
V15.0.0  2018/06  10 p.
V14.0.0  2017/03  10 p.
V13.0.0  2017/03  10 p.
Rapporteur:
Mr. Evans, Tim P.
VODAFONE Group Plc

Content for  TS 55.242  Word version:  18.0.0

Here   Top
0 Introduction  1 Scope  2 References  3 Definitions and abbreviations  4 Introductory information  5 Test data  $ Change History 

 

0  Introduction  p. 4

The present documenthas been prepared by the 3GPP Task Force, and gives a detailed specification of the 3GPP integrity algorithm GIA4.
The present document is the second of three, which between them form the entire specification of the 3GPP Integrity Algorithm GIA4:
  • 3GPP TS 55.241: "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Specification of the GIA4 integrity algorithms for GPRS; GIA4 specification".
  • 3GPP TS 55.242: "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Specification of the GIA4 integrity algorithms for GPRS; Implementers' test data".
  • 3GPP TS 55.243: "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Specification of the GIA4 integrity algorithms for GPRS; Design conformance test data".
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1  Scope  p. 5

The present document defines the implementers test data of the 3GPP integrity algorithm GIA4.

2  References  p. 5

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
  • References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
  • For a specific reference, subsequent revisions do not apply.
  • For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
[1]
TR 21.905: "Vocabulary for 3GPP Specifications".
[2]
TS 55.241: "Specification of the GIA4 encryption algorithms for GPRS; GIA4 specification".
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3  Definitions and abbreviations  p. 5

3.1  Definitions  p. 5

For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.

3.2  Abbreviations  p. 5

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905.

4  Introductory information  p. 5

4.1  Introduction  p. 5

The integrity algorithm GIA4 computes a 32-bit MAC (Message Authentication Code) of a given input message using integrity key KI128. The approach adopted uses KASUMI [2] in a form of CBC-MAC mode.

4.2  Notation  p. 5

4.2.1  Radix  p. 5

"0x" is used to indicate hexadecimal numbers.

4.2.2  Conventions  p. 6

The assignment operator "=", is used as in several programming languages. The following:
<variable> = <expression>
means that <variable> assumes the value that <expression> had before the assignment took place. For instance,
x = x + y + 3
means
(new value of x) becomes (old value of x) + (old value of y) + 3.

4.2.3  Bit/Byte ordering  p. 6

All data variables in this specification are presented with the most significant bit (or byte) on the left hand side and the least significant bit (or byte) on the right hand side. Where a variable is broken down into a number of sub-strings, the left most (most significant) sub-string is numbered 0, the next most significant is numbered 1 and so on through to the least significant.
For example an n-bit MESSAGE is subdivided into 64-bit substrings MB0,MB1…MBi so for a message:
0x0123456789ABCDEFFEDCBA987654321086545381AB594FC28786404C50A37…
The resulting notation is:
MB0 = 0x0123456789ABCDEF
MB1 = 0xFEDCBA9876543210
MB2 = 0x86545381AB594FC2
MB3 = 0x8786404C50A37…
In binary this would be:
000000010010001101000101011001111000100110101011110011011110111111111110…
with
MB0 = 0000000100100011010001010110011110001001101010111100110111101111
MB1 = 1111111011011100101110101001100001110110010101000011001000010000
MB2 = 1000011001010100010100111000000110101011010110010100111111000010
MB3 = 1000011110000110010000000100110001010000101000110111…
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4.3  List of variables  p. 6

A, B
are 64-bit registers that are used within the function to hold intermediate values.
BLOCKS
an integer variable indicating the number of successive applications of KASUMI that need to be performed.
CONSTANT-F
a 32-bit parameter which is constant for any given FRAMETYPE input.
DIRECTION
a 1-bit input indicating the direction of transmission (uplink or downlink).
FRAMETYPE
an 8-bit input to the function indicating the type of frame to be protected.
INPUT-I
a 32-bit time variant input to the function.
KI128
the 128-bit integrity key.
KM
a 128-bit constant that is used to modify a key.
M
an input to the function which specifies the number of octets of message to be MAC'd (1-65536).
MAC
the 32-bit message authentication code (MAC) produced by the function.
MESSAGE
the input octet stream of length M octets that is to be processed by the function.
PS
is the input padded string processed by the function.
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5  Test data  p. 7

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

$  Change History  p. 8

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