Patent ID: 8239957
Filing Date: 2012-08-07
Classification: G06F,H04L

Abstract:
1. A method for preventing rendering of content at overlapping time periods on more rendering devices than permitted by a license associated with the content, the method comprising: transmitting the following to a rendering device of a user: the content; first software that is operative to receive the content and to associate keys with the content; identification information (ID) that is associated with the user; and second software that comprises a player for rendering the content; generating, at the rendering device of the user, an asymmetric key pair comprising a public key and a private key; producing a digital package comprising: the key pair; the content; and the ID; receiving the following information from the rendering device of the user during rendering of the content: a number representation X which comprises a number representation in bits of a result obtained from encrypting together a number representation of a present time interval and the ID, both encrypted with the public key of the key pair; and a number representation Y which comprises a number representation in bits of a share (SH) of the private key of the key pair, wherein the share SH comprises a portion of the private key such that the private key may be revealed when n+1 shares of the private key are known, but when only n shares of the private key or less than n shares are known, the private key cannot be revealed, where n is a number of rendering devices permitted by the license; receiving additional number representations X and additional number representations Y which are paired with the additional number representations X from a plurality of rendering devices which attempt to render the content, said plurality of rendering devices not including the rendering device of the user, at least some of said plurality of rendering devices having received the digital package from the rendering device of the user and having made use of the key pair comprised in the digital package to produce number representations X and Y; detecting an attempt to render the content at overlapping time periods on more rendering devices than permitted by the license associated with the content based on a determination that n+1 of the number representations X are identical, and n+1 of the number representations Y which are paired with the n+1 number representations X are different; reconstructing the private key of the key pair, in response to the detecting, by using the shares in the n+1 number representations Y; identifying the ID based on the reconstructed private key; and preventing rendering of the content on all rendering devices associated with the ID.