2.2.5.1.4 EXTENSION

An EXTENSION structure is used in the EXTENSION_VECTOR structure (section 2.2.5.2.4) as the Extensions field in the NEGO_MESSAGE structure, as specified in section 2.2.6.3

 struct
 {
   ULONG ExtensionType;
   BYTE_VECTOR ExtensionValue;
 } EXTENSION; 

ExtensionType: A ULONG that indicates how the extension data should be interpreted. All negative extension types (the highest bit is set to 1) are critical. If the receiver does not understand a critical extension, the authentication attempt MUST be rejected.

ExtensionValue: A BYTE_VECTOR structure that contains the extension data.