2.2.3.2.3.4.6 DHGroup
The DHGroup registry value specifies the type of Diffie-Hellman group used for Internet Key Exchange (IKE) key generation during MM SA negotiation [RFC4306]. This value MUST be of type REG_DWORD. Allowed values for this registry value are the same as those for dwDhGroup in ROUTER_CUSTOM_IKEv2_POLICY_0. If the value is not specified for this registry value, or if this registry value is not present, the default value DH_GROUP_2 (0x2) is assumed.