Patent ID: 7711727

Claim:
A computer program product having a plurality of executable instruction codes stored on a computer readable medium, for selectively sharing a plurality of distributed access-controlled documents, comprising: a plurality of content providers comprising a set of instruction codes for cooperating to create a privacy-preserving index structure; a set of instruction codes for grouping the content providers into a plurality of privacy groups; a set of instruction codes for passing a content vector from a first content provider in a privacy group of the plurality of privacy groups to a second content provider in the privacy group of the plurality of privacy groups; a set of instruction codes for enabling the first and second content providers to operate on the content vector with a randomized algorithm; a set of instruction codes for sending a plurality of content vectors to a designated host, each content vector of the plurality of content vectors corresponding to a respective privacy group of the plurality of privacy groups; a set of instruction codes for aggregating the plurality of content vectors into a materialized index comprising the privacy-preserving index structure; the privacy-preserving index structure comprising a set of instruction codes for mapping a plurality of keywords representing a content to be shared to the plurality of content providers; and a set of instruction codes for returning a list of the content providers having a subset of the content to be shared of the access-controlled documents that comprise a set of the keywords that satisfy a query.