2.2.4 AUTH_CGA Authentication Method Packet

AUTH_CGA is an authentication method within an ISAKMP SA payload, as specified in [RFC2407] section 4.6.1. The format of the SA payload is the following, as specified in [RFC2408] section 3.4.

  • A number of Proposal payloads, as specified in [RFC2408] section 3.5.

  • Within each Proposal payload, there is a number of Transform payloads, as specified in [RFC2408] section 3.6.

  • Within each Proposal payload, there is a number of Data Attributes payloads, as specified in [RFC2408] section 3.3. In a Data Attribute payload, an authentication method is indicated by the value 0x0003 in the Attribute Type field of the Data Attribute payload, as specified in [RFC2409] Appendix A. The particular authentication method is determined by the value of the Attribute Value field, as specified in [RFC2409] Appendix A.

The Data Attribute payload for the AUTH_CGA Authentication method has the format seen in the following AUTH_CGA packet.


0


1


2


3


4


5


6


7


8


9

1
0


1


2


3


4


5


6


7


8


9

2
0


1


2


3


4


5


6


7


8


9

3
0


1

A

Attribute_Type

Attribute_Value

A - One (1 bit): This field MUST be set to 1.

Attribute_Type (15 bits): For the AUTH_CGA authentication method, this field MUST be set to the value 0x0003. This value corresponds to the authentication method, as specified in [RFC2409] Appendix A.

Attribute_Value (2 bytes): For the AUTH_CGA authentication method, this field MUST be set to the value 0xFDED in network order. This value is from the private authentication method range, as specified in [RFC2409] Appendix A.