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. Type 112 for Digest-Entity-Body-Hash Length >= 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.