e context
                        in which OTP is being used&gt;

   An example of an extended challenge indicating support for OTP
   extended responses and for a mythical response set "foo" is:

      otp-md5 123 mi1234 ext,foo

   An example of an extended response using a mythical type named "foo"
   is:

      foo:some data:some more data:12345

2.2. Requirements

   A server compliant with this specification:

      1. MUST be able to receive and parse the general form of an
         extended response