XPost: alt.privacy, sci.crypt   
   From: heremypants@hushmail.com   
      
   On Fri, 11 Feb 2011 19:42:13 -0600, Jeffrey Goldberg wrote:   
      
   > On 11-02-11 3:02 PM, hierophant wrote:   
   >   
   >> On Fri, 11 Feb 2011 13:33:07 -0600, Jeffrey Goldberg wrote:   
   >   
   >>> Ron may have needed several attempts at the replay attack, but   
   >>> the essence was a replay, not brute force.   
   >>   
   >> Is not a replay attack requirement that there be some style of capture   
   >> of the attacking mechanism (in this case specific Parseltongue from   
   >> Harry)?   
   >   
   > Yes. And that is exactly what Ron did.   
   >   
   > "But how did you get in there?" [Harry] asked, staring from the fangs to   
   > Ron. "You need to speak Parseltongue!"   
   >   
   > "He did!" whispered Hermione. "Show him, Ron!"   
   >   
   > Ron made a horrible strangled hissing noise.   
   >   
   > "It's what you did to open the locket," he told Harry apologetically. "I   
   > had to have a few goes to get it right, but," he shrugged modestly, "we   
   > got there in the end."   
   >   
   > Ron explicitly said that he was trying to repeat the sounds that Harry   
   > had made in Parseltongue to open the locket.   
   >   
   >> Ron was performing a mimicry,   
   >   
   > Yes, he was mimicking (replaying) an transmission he'd intercepted   
   > (overheard) that had been used to issue the "open" command in Parseltongue.   
   >   
   >> hissing sounds and tones randomly but within a set of Parseltongue   
   >> sounds he had to choose from.   
   >   
   > He was not picking randomly from the entire domain of Parseltongue-like   
   > sounds. He was trying to replicate a specific signal he'd heard which he   
   > knew authenticates and authorizes one to open things.   
   >   
   > It was a replay attack.   
   >   
   >> Sounds much like a brute force, dictionary-like attack to me. ;)   
   >   
   > I will give you the benefit of the doubt and acknowledge that you may   
   > have mis-remembered the particular conversation from Deathly Hallows.  I   
   > hope that now it has been replayed, you see that this far better fits   
   > the definition of a replay attack than a brute force one.   
   >   
   > The only reason that I remembered it was because when I read it   
   > initially I thought that Parseltongue should be such that a replay   
   > wouldn't work.   
   >   
   > In that conversation Harry should have heard Ron's imitation as "open".   
   >   That is, if Ron's imitation was good enough to open the Chamber of   
   > Secrets, it should have been good enough to sound "real" to Harry.   
      
   Appreciate the education, Jeffrey, thanks!   
   --   
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