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Jeff Kelley
Works at Detroit Labs
Attended University of Michigan
Lives in Macomb, MI
2,028 followers|6,461 views
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Jeff Kelley

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“We are not aware of a better DRM scheme than ours.”
 
I bought a digital video download today that required a video player from Leaping Brain. As usual, the proprietary player wasn't great and to transfer it to my iPhone I'd need another proprietary player. Ugh. But I browsed around and found that the video had been downloaded into a hidden directory as a bunch of .mov files. Great, except none of the files would play.

It turned out the actual player, launched from their compiled app, was a Python wrapper around some VLC libraries. Nothing funny going on, as far as I could tell, but when I tried to launch the player directly, nothing happened. The compiled app was modifying the .mov files right before they were loaded into the player, and then reverting the file on disk. According to http://leapingbrain.com/mod-machine/faq/:

 "We apply our BrainTrust™ proprietary video encryption to your movies before we upload them to our servers. If someone ever was able to gain access to your content, the files would be useless and unplayable, because they are stored in a scrambled, encrypted format. Once downloaded to the user’s hard drive, the files are still encrypted and only readable via the MOD Machine Player by a legitimate owner. We are not aware of a better DRM scheme than ours. Where Windows Media DRM is easily crackable, and doesn’t run on Macs, BrainTrust™ works great on Windows 8, Vista, Windows XP and Mac, and is virtually uncrackable."

Virtually uncrackable? Well, since they load the file from a Python script, it's easy to make a copy of the "decrypted" file before it's reverted. Having done so, I was curious to see the encryption scheme. By comparing the binary files, I discovered the "proprietary video encryption" algorithm: for the first 15kB, each 1kB block has its initial bytes xor'd with the string "RANDOM_STRING". That's the "scrambled, encrypted format" that leaves these files "useless and unplayable".
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that was my first attempt at encryption - when I was 8
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Jeff Kelley

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My book is out! Published by Apress, Learn Cocoa Touch is available now in paperback and on Kindle (iBooks coming soon). Buy ten today!
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Maybe. Shoot me an e-mail (slaunchaman@gmail.com) and let’s talk.
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Jeff Kelley

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It’s my money and I want it meow!
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Jeff Kelley

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That’s a lotta cupcakes.
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This is proof how Groupon deals can go badly really fast. I'm amazed that companies don't pay attention and put limits. As a business owner myself, back when Groupon was all the hype, I thought about how it might benefit us, but when I really thought about it, I realized sales services like this have no value unless you rely heavily on repeat customers. For a bakery it's not a bad idea, as long as you can afford 1/4th your normal retail price, but like I said, you HAVE to put a limit on the total purchases.
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Every designer should read this.
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I can vouch for this.
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In his circles
94 people
Have him in circles
2,028 people
Work
Occupation
iOS Developer
Employment
  • Detroit Labs
    Mobile Guru, 2011 - present
  • Vectorform
    Senior Apple Media Architect, 2010 - 2011
  • University of Michigan
    Macintosh Developer, 2007 - 2010
Places
Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
Currently
Macomb, MI
Previously
Clarkston, MI - Farmington Hills, MI - Ann Arbor, MI - Okemos, MI
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Tagline
Detroit, MI iOS developer.
Introduction
I'm an iPhone/iPad developer. I graduated from the University of Michigan (Ann Arbor campus) in 2008 with a degree in Philosophy.
Bragging rights
Has given talks at several CocoaHeads meetings (both Detroit and Ann Arbor) as well as a mobile development conference in Detroit.
Education
  • University of Michigan
    Philospohy, 2004 - 2008
  • Okemos High School
    2000 - 2004
Basic Information
Gender
Male
Relationship
Married