GDOI Statements

BCD.

GDOI (Group Domain of Interpretation) is a protocol that is used to establish a group key for secure communication between multiple devices. Here are the explanations of the three true statements about GDOI:

A. GDOI uses TCP port 848. This statement is false. GDOI uses UDP port 848 to communicate between devices.

B. The GROUPKEY_PULL exchange is protected by an IKE phase 1 exchange. This statement is true. GROUPKEY_PULL is an exchange in GDOI where the member of the group requests the current group key from the Key Server. This exchange is protected by an IKE phase 1 exchange, which establishes a secure connection between the member and the Key Server.

C. The KEK protects the GROUPKEY_PUSH message. This statement is true. GROUPKEY_PUSH is an exchange in GDOI where the Key Server sends the updated group key to the members of the group. This message is encrypted using the Key Encryption Key (KEK), which is established during the GDOI group registration process.

D. The TEK is used to encrypt and decrypt data traffic. This statement is true. After the group key is established, the Traffic Encryption Key (TEK) is used to encrypt and decrypt data traffic between the members of the group.

E. GDOI does not support PFS. This statement is false. Perfect Forward Secrecy (PFS) is supported by GDOI. PFS ensures that even if the long-term key is compromised, past communications remain confidential. GDOI provides PFS by using a new KEK for every GROUPKEY_PUSH message.