Mobile DRM in Japan: another close look

On this blog and in my Japan Media Review paper, I’ve mentioned several times the restrictive DRM mechanisms inside Japanese keitai (mobile phones). Since about a year has passed since the last update, it’s time for another look — study object is AU’s W32T (the numbers below correspond to the Japanese manual‘s page numbers).

First, a quick intro for those unfamiliar with the concept: basically all Japanese keitai are internet enabled, and have a mail client and one or two browsers built in. This browser can be used for accessing websites, or else, for downloading content on-the-go. Downloaded or external content can be saved on the usually rather small internal memory unit (a couple of MB) or on removable flash memory (usually a few hundred MB). Some models also have an infrared port or are Bluetooth enabled, thereby giving its owner another way to move content from or onto his/her device.

And of course, DRM galore:

  • The basic rule is that almost every piece of content that touches your keitai gets a “copy-protection ON/OFF” flag (p 186). Notable exceptions are BMP and SWF files, which are always locked; DCF-type JPGs (= your own pictures), PIM data and email inboxes on the other hand are always unlocked (lucky us!).
  • Copy-protected files cannot be forwarded via mail (p 109) nor exchanged via Bluetooth (p 172). Furthermore, any form of editing is prohibited: this means you cannot resize copy-protected movies (p 179) or images (p 176), add GPS metadata to them (p 180) or reuse them as part of a “photo-mix” (p 344). Even using a copy-protected movie as an incoming call animation is forbidden (p 167).
  • Moving (not copying!) copy-protected files to the miniSD removable flash memory is possible, but only in case the content provider explicitly allows it. Caveat: when you move copy-protected files from the internal phone memory to the miniSD card, the files in question are automatically put in a (probably CPRM powered) “secure” folder, preventing them from being accessed with other devices than the keitai they were originally downloaded or received with (or a new keitai using the same number and carrier). Also interesting to know is that, in case you try to get access to the secure folder with a device other than the W32T, there is a chance the directory in question is corrupted and the data within might become unusable… (p 185)
  • EZ Movies (p 212) and EZ Channel mini-broadcasts (p 233) not only come with copying restrictions, but usually also have playback limitations built in, allowing the content provider to exactly define the number of playbacks customers can enjoy (play-count and absolute/relative time based expiration dates are possible). Free EZ Channel content for instance can only be played 3 times, and the downloaded TAR package is automatically deleted once a new episode becomes available.
  • The W32T, as well as most other recent keitai, supports playback of personal, non-downloaded movies or songs, provided they’re in the correct format — of course, there are non-official tools to help you with the conversion process. However, once you copy or move the media files in question from the miniSD card to the phone’s internal memory, the files’ copyright-flag is switched to ON, locking them to your mobile phone and inhibiting further processing (such as forwarding or resizing).
  • Another copyright related nag: the W32T’s Opera powered browser has no image download or select+copy functionality. I am not sure whether this was a copyright inspired design decision or not, but a few lines of JavaScript easily work around this lack of functionality.

That’s all for now. If you think that is a lot of DRM in such a small device, then bear in mind that I haven’t even touched DRM enabled mobile ebook reader applets, LISMO‘s DRM, or OneSeg Mobile TV DRM — something for future entries…

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  1. Do ypu know decrypt secured file?

    I know KDDI DRM FILE(KDR) is protected by telephone number.


    » ken on May 24th, 2006 at 12:49