RADIUS attribute from rfc5090


When using the qop-value 'auth-int', a hash of the HTTP-style
         message body's contents is required for digest calculation.
         Instead of sending the complete body of the message, only its
         hash value is sent.  This hash value can be used directly in
         the digest calculation.

         The clarifications described inabout
         the hash of empty entity bodies apply to the Digest-Entity-
         Body-Hash Attribute.  This attribute MUST only be sent in
         Access-Request packets.
         112 for Digest-Entity-Body-Hash
         >= 3Text
         The attribute holds the hexadecimal representation of
         H(entity-body).  This hash is required by certain
         authentication mechanisms, such as HTTP Digest with quality of
         protection set to 'auth-int'.  RADIUS clients MUST use this
         attribute to transport the hash of the entity body when HTTP
         Digest is the authentication mechanism and the RADIUS server
         requires that the integrity of the entity body (e.g., qop
         parameter set to 'auth-int') be verified.  Extensions to this
         document may define support for authentication mechanisms other
         than HTTP Digest.