[mythtv-users] Be vewy, vewy quiet! We'a huntin' pirates! hehehehehehe!

Sam Varshavchik mrsam at courier-mta.com
Fri Jun 22 11:06:07 UTC 2007

Joseph Caputo writes:

> On 6/21/07, Sam Varshavchik <mrsam at courier-mta.com> wrote:
> [snip]
>> I believe that it is possible to implement technical measures to prevent
>> wholesale piracy of program guide data, yet allow legitimate usage by
>> MythTV, with some minimal impact.
> I don't recall "wholesale piracy" being the issue -- I don't think
> anyone was *stealing* the guide data in its totality (just stealing
> bits of it at a time...).  I may be wrong...
> [snip]
>> On the other hand, look at an individual MythTV subscriber? What does he/she
>> "use"?
>> As far as I can tell, you and me only "use" program details about stuff we
>> record. You and me also need to do simple keyword searches, and perhaps get
>> quick snapshots of abbreviated program titles for short blocks of time, to
>> display the channel grid.
>> That's the difference. We do not need to really know the details of all
>> programs on every channel, 24x7. Just the stuff that we watch. That's the
>> technical difference between us, legitimate subscribers, and whoever's
>> stealing and reselling whole program data. That's the key difference that
>> the technical solution can explot.  Here's how.
> Have you used Myth's advanced scheduling features much?  How would you
> be able to set up advanced rule-based schedules if you don't download
> all of the data about every program in the schedule?  For instance, if
> I want to record everything starring John Wayne, or anything
> containing the phrase "World War II" in the description (which I can
> do now with complete access to the DataDirect guide info), how would I
> do that without *all* of the guide data available to query?

That's just a form of keyword-based search, which can be done without 
revealing entire guide data. What you need to do, in addition to encrypting 
program details using a symmetric cipher, with a per-program key, is to have 
a second copy of the program guide where each individual word W is replaced 
by H(w+secret). H is a hash function, MD5/SHA1/SHA256/whatever. "secret" is 
a secret known only to the server. To effect the search, you'll need to ping 
the server with w, the server returns H(w+secret), and that's what you run 
your search with. I've left out some minor details, but that's the general 

I admit that, without some crafty hacking, you'll lose the ability to run 
arbitrary SQL searches, but this'll work for most searches that people use. 
Once your search finds individual programs, you'll then ping the server to 
get it's cipher, and obtain the program details.

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