One way of decrypting data stored on most HD DVDs released so far requires the number "09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0". Although this number is essential to have if one is going to write HD DVD player software which will play those titles, apparently web sites which have published this number have been receiving "take-down" or "cease-and-desist" orders requesting and requiring that the number be removed from their sites. Many individuals considered these requests to be misuses of the poorly-written Digital Millennium Copyright Act and mounted a "posting rebellion" in late April and early May of 2007, posting copies of the key on various blogs and web sites.
The furor over that key notwithstanding, they key itself is not only "revocable" (meaning it can be rendered invalid – with as-yet-unknown implications to the purchasers of the HD DVDs encoded with it), but another "irrevocable" crack was discovered some two weeks earlier.
- 2007-04-30 Spread this number: a somewhat informal explanation of the number's significance