Like all matter in the universe, MPEG-4 files are also made of "atoms" - it's the term given for the set of nested data that comprises the structure of an MPEG-4 file. Atoms are key to the way the audio and video data within an MPEG-4 file are accessed. They figure in how Apple's digital rights management (DRM) scheme is used to protect music file purchases from its iTunes Music Store. (Apple uses the AAC file format; AAC is the audio layer in MPEG-4 files.) Atoms also factor in how hymn is able to "scrub" protected AAC files of Apple's DRM.
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hymn is a decryption program based on the work of Jon Lech Johansen , who first reverse-engineered Apple's DRM scheme (called "FairPlay"). The original author of the hymn code, which he released under the GNU General Public License, has never come forward, and prefers to remain anonymous.
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The current maintainer of hymn goes by the handle "FutureProof," who describes himself as "older than 30" and living "someplace where there's a lot of snow outside now" (the below interview with him was conducted in January). By profession, he works as a software engineer. He developed JHymn, a more user-friendly Java implementation of the original command-line version of hymn. His present goals for the project are to improve the JHymn user interface, and the effectiveness of its removing of the FairPlay DRM.
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FutureProof spoke with us about the continuing development of hymn/JHymn, and explained what other tricks Apple has up its sleeve to cripple files purchased from the iTunes Music Store that the user has decrypted.