The Option Length field must be 2. The payload of this Option consists of a 32 bit value which identifies the authentication scheme in use, followed by that scheme's data. It is expected that this option will be used when the number of packets that require authentication is too small to justify the cost of a full negotiation, when the operation is time critical, or when security negotiation cannot take place. The processing cost of this option is expected to be higher than that of a negotiated authentication option, and it might not provide guarantees as hard as the latter, especially with respect to replay protection. No specific security mechanism has been specified in this document, although an option number has been reserved.
Further research is required.
Options that have their Private bit set should be ignored by the implementation at this stage. All Options defined in this document require no action from the active node. Information on the Options may also be made available to the packet program during its evaluation. Information on the Options may be used by the evaluation environment directly. There is no priority for dealing with Option parsing failure.