Cryptanalysis researchers demonstrated flaws in HDCP as early as 2001. In September 2010, an HDCP master key that allows for the generation of valid device keys was released to the public, rendering the key revocation feature of HDCP useless.[8][9] Intel has confirmed that the crack is real,[10] and believes the master key was reverse engineered rather than leaked.[11] In practical terms, the impact of the crack has been described as “the digital equivalent of pointing a video camera at the TV”, and of limited importance for consumers because the encryption of high-definition discs has been attacked directly, with the loss of interactive features like menus.[12] Intel threatened to sue anyone producing an unlicensed device.[11]