Hash File Numbers and Copyright Trolls

OK, someone brought to my attention the fact that all this hash file # stuff is a bit confusing.  I decided to do a little update and explanation.  The following deals with the movie and hash file #s associated with the “The Thompsons” copyright troll cases.  My previous “Thompsons” posting.  Note: The significance of this applies equally to other BitTorrent copyright troll cases.

The movie associated with the different hash file #s in these cases is the same – The Thompsons.  Same in the sense that for these hash files #s, the movie is a key part of it.

So why are there different hash file #s for the same movie in these cases?  This is due to a difference in the digital file of each ‘different’ copy of the movie.  Two main reasons for the differences are:

  1. The initial copy was in some way changed – possibly had parts removed/edited.  Example: Removing the introduction or credits portion of the movie and saving it.
  2. The movie was saved as a different digital format than other versions (.mov, .mp4, .avi, etc.). This could have also been done after edits/changes were made to the content of the movie (see above).

The movie is generally the same content, but it is still a different file when compared to the others – “The devil is in the details.

Why can’t Plaintiff lump all the different hash files for the same movie into one case?  All the Does are in the right jurisdiction and in the same time frame for the alleged activity. The reason is because the BitTorrent clients DO NOT download/share files (a movie here) that are “similar.”  A BitTorrent client is only going to download/share the exact file that it is directed to after matching up the hash file number.  It is a little more technical than that, but just go with it.  To a BT client, a different hash file # is completely different – a 160 Bit difference.  The difference is like comparing a Sperm Whale to a bowl of petunias.

False Statement (my opinion).  By including IP addresses with different hash file numbers for the same movie into a single case, the Plaintiff is providing a false statement to the court.

Joinder1As the BitTorrent client is only going to download/share files of the same hash value, ALL the other IP addresses CANNOT be properly joined.  They do not “…arise out of the same occurrences or transactions, or series of occurrences
or transactions…”  The different file hash values mean different occurrences/transactions – PERIOD.  “Same” does not mean “similar.”  Plaintiff could try to blame the technical experts, but it is still their responsibility to provide accurate information.  The attorney should at least be knowledgeable about what constitutes permissible joinder in their cases.  Failure to do so could result in FRCP Rule 11 (see section (a) (3)) sanctions.

Fun with Hash file #s.  Here are two images of a Prenda parody.   🙂

prenda_parody1prenda_parody2The second image has a very small Red dot added to the center of Bart’s shirt.  Both images are essentially the same; so people may not even notice the difference.  The parody aspect of the images are the same (no overall content or meaning change), but they are still different files.  Now putting both files through a mathematical calculation for SHA1 will give you different results.   Results   You can see that the SHA1 file #s are different.  In fact, all it takes is one single Bit to be changed and the hash # will change.  As the SHA1 hash is a 160 Bit, the chance of finding another file with the same value is astronomical.

Bottom line – lumping different hash files #s for the same movie into a single case does NOT support joinder.  A Pro Se Doe or Doe defender should not have any problem bringing this to the attention of a court and making a motion to sever improperly joined IP addresses.  Now Plaintiff can just refile new cases, but at least they will get the joinder right.

DieTrollDie 🙂

About DieTrollDie

I'm one of the many 'John Does' (200,000+ & growing in the US) who Copyright Trolls have threatened with a civil law suit unless they are paid off. What is a Copyright Troll? Check out the Electronic Frontier Foundation link - http://www.eff.org/issues/copyright-trolls
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3 Responses to Hash File Numbers and Copyright Trolls

  1. but wait! theres more... says:

    very nice.
    we’ve been struggling with verbiage on this very topic.
    there’s also something about the hash# of the (dot) .torrent file vs. the hash # of the actual contents file…
    -Hash functions are mostly used to accelerate table lookup or data comparison tasks such as finding items in a database
    -Hash functions are related to (and often confused with) checksums, check digits, fingerprints, randomization functions, error correcting codes, and cryptographic hash functions. Although these concepts overlap to some extent, each has its own uses and requirements and is designed and optimized differently.

    IANAL – but the Plaintiff may be providing another oversimplified, misleading statement to the courts.

    • that anonymous coward says:

      Or attempting the Jedi hand wave and hoping people will say oooh technology and accept it.

  2. Nobody says:

    It’s very simple: it might look the same to us, but the programs don’t know that and they won’t even attempt to share it with each other unless it has the same hash. So people sharing different versions are not working together at all.

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