RADIUS attribute from rfc5090

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Digest-Auth-Param

This attribute is a placeholder for future extensions and
         corresponds to the auth-param parameter defined in.  The Digest-Auth-Param is the mechanism
         whereby the RADIUS client and RADIUS server can exchange auth-
         param extension parameters contained within Digest headers that
         are not understood by the RADIUS client and for which there are
         no corresponding stand-alone attributes.

         Unlike the previously listed Digest-* attributes, the Digest-
         Auth-Param contains not only the value but also the parameter
         name, since the parameter name is unknown to the RADIUS client.
         If the Digest header contains several unknown parameters, thenthe RADIUS implementation MUST repeat this attribute, and each
         instance MUST contain one different unknown Digest
         parameter/value combination.  This attribute MUST ONLY be used
         in Access-Request, Access-Challenge, Access-Accept, and
         Accounting-Request packets.
   Type
         117 for Digest-Auth-Param
   Length
         >= 3
   Text
         The text consists of the whole parameter, including its name,
         the equal sign ('='), and quotes.

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