History

The discovery of the processing key capable of decrypting all HD DVD discs began on December 26, 2006. On this day, a person by the alias of muslix64 published a small open-source utility (software) called BackupHDDVD, and its source code, on a forum on the doom9 website. (To read the author’s narration of how he decrypted his first movie, click here). The software, capable of decrypting AACS protected content, was only useful if the user knew the encryption key. Although muslix64 assured his fellow bloggers that finding such keys in memory was rather easy, having to search for each individual key was rather tedious, when not difficult. The utility however, proved to be extremely helpful for other crackers that were still searching for that unique key to decrypt all discs.

From then on, people began searching for hidden keys of certain movies in RAM (memory). Using programs like WinDVD, people started finding title keys and volume keys of certain movies. On January 13, 2007, the first title keys began to appear on the internet. One of them, posted on the page pastebin.com in the form of a riddle, gave the user a number, which, once converted to hexadecimal, provided the title key for the movie Serenity. Later that day, the movie was uploaded to a private torrent tracker and became the first cracked movie available to the public. By this time, the AACS had already noticed that title keys of certain movies were available to the public, and started taking action to prevent the widespread of the keys.

Serenity became the first cracked HD DVD movie publicly available.

On February 11, 2007, a 128-bit encryption key, written in hexadecimal as 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0, was posted by arnezami on the doom9 forum. This processing key, which in decimal notation is written as 13,256,278,887,989,457,651,018,865,901,401,704,640, proved to be one of the cryptographic keys of the HD DVD. This was a huge discovery, since it meant that the key to decrypt all HD DVDs had finally been found. According to arnezami, the processing key was hidden in a memdump file (memory) and, by using a utility created by other members of the forum, he was able to find it (to read arnezami’s description of how he found the processing key, click here).

A screenshot of the forum doom9, showing the post where arzenami first announced the HD DVD Processing Key.

On April 16, 2007, the AACS LA announced that it had invalidated the decryption keys associated with most software HD DVD players, and that discs encrypted and mastered after that date would not be able to play unless the software was updated. Even when the processing key found by arzenami was only “valid” for discs released up to that date, the discovery was a giant success against the AACS protection systems and it encouraged people to persist in their quest to “crack” HD DVD discs.

One month later, on May 23rd, a new processing key was posted on Edward Felten's Freedom to Tinker Blog, which was able to decrypt all the new discs mastered after April 16.

On to Impact.