J.1 Elements for Authenticating Requests
33.1803GPPRelease 17Security of the Mission Critical (MC) serviceTS
J.1.1 General
This clause describes the functional definitions and contents for the Element for Authenticating Requests (EARs). EARs may be used to authenticate and potentially authorise signalling requests within the MC System.
Each EAR consist of a series of information elements. The standard format of an EAR and the encoding rules for each type of information element follow that defined for the MCPTT Off-Network Protocol (MONP) as documented in Annex I of 3GPP TS 24.379 [49].
J.1.2 Format of an EAR
This subclause defines the contents of an EAR message. The EAR provides details of the request and associates that request with an authenticated identity. The EAR shall be signed using the mechanism defined in Clause 8.5.5. For the contents of the EAR see Table J.1.2-1.
Message type: EAR PAYLOAD
Direction: Attached to a signalling request as defined in Clause 9.6.2.
Table J.1.2-1: EAR PAYLOAD message content
|
IEI |
Information Element |
Type/Reference |
Presence |
Format |
Length |
|
EAR message ID |
Message type |
M |
V |
1 |
|
|
Date and time |
Date and time |
M |
V |
5 |
|
|
EAR ID |
EAR ID J.1.3 |
M |
V |
16 |
|
|
Source Role |
Role ID J.1.4 |
M |
V |
1 |
|
|
Source ID |
Entity ID |
M |
LV-E |
2-x |
|
|
Target Role |
Role ID J.1.4 |
M |
V |
1 |
|
|
Target ID |
Entity ID J.1.5 |
M |
LV-E |
2-x |
|
|
uu |
Request |
Request J.2 |
O |
TLV-E |
3-x |
J.1.3 Format of an EAR ID
The EAR ID information element uniquely identifies the EAR.
The EAR ID information element is coded as shown in Figure J.1.3-1 and Table J.1.3-1.
The EAR ID information element is a type 3 information element with a length of 16 octets.
|
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
|
|
EAR ID value |
octet 1 octet 16 |
|||||||
Figure J.1.3-1: EAR ID value
Table J.1.3-1: EAR ID value
|
EAR identifier value (octet 1 to 16) The EAR ID contains a number uniquely identifying an EAR. The value is a universally unique identifier as specified in IETF RFC 4122 [14]. |
J.1.4 Format of an entity’s Role ID
The purpose of the Role ID information element is to identify the role of the entity and the type of entity ID used by the entity.
The value part of the Role ID information element is coded as shown in Table J.1.4-1.
The Role ID information element is a type 3 information element with a length of 1 octet.
Table J.1.4-1: Role IDs
|
Bits |
|||||||||
|
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
||
|
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
MC Service client |
|
|
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
MC Service group |
|
|
0 |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
MC Service function/server |
|
|
All other values are reserved. |
|||||||||
More fine-grained role identifications may be provided using an Authorised Identity (as defined in Clause 9.6.3).
J.1.5 Format of an MC Entity ID
The MC Entity ID information element is used to indicate an MC Service user ID, an MC Group ID or an FQDN associated with an MC function. The type of Entity ID is defined by the Role ID as defined Clause J.1.4.
The MC Entity ID information element is coded as shown in Figure J.1.5-1 and Table J.1.5-1.
The MC Entity ID information element is a type 6 information element.
|
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
|
|
Length of MC Entity ID contents |
octet 1 |
|||||||
|
octet 2 |
||||||||
|
octet 3 |
||||||||
|
MC Entity ID contents |
||||||||
|
octet n |
||||||||
Figure J.1.5-1: MC Entity ID information element
Table J.1.5-1: MC Entity ID information element
|
The MC Entity ID is contained in octet 3 to octet n. The MC Entity ID may be an MC Service user ID, MC Group ID or an FQDN associated with an MC function. |