Abstract: A system and method for sharing files securely includes server software on a first device configured to communicate with server software operating on one or more other preauthorized devices, such as a second device. The servers communicate with each other securely using cryptographic information exchanged during a preauthorization phase using a range-limited communication channel. The server on the first device obtains file information from the other preauthorized device(s) and combines the information with local file information from the first device. This combined file information is sent to client software operating on the machine, which presents the combined file information to users.

Abstract: One embodiment of the present invention provides a system that detects malicious data in an ad-hoc network. During operation, the system receives data at a node in the ad-hoc network, wherein the data was sensed and redundantly communicated to the node by other nodes in the ad-hoc network. Note that in this ad-hoc network, a given node senses data associated with itself and with proximate nodes in the ad-hoc network. In this way, proximate nodes in the ad-hoc network can redundantly sense data about each other. Next, the system determines at the node if the received data, along with data sensed locally by the node, is consistent. If not, the system uses a model which accounts for malicious nodes to determine an explanation for the inconsistency.

Abstract: Techniques for protecting non-public information in a mobile environment are provided. A request for non-public information about users in a mobile environment is received. Privacy policies, non-public and optional public information about the users affected by the request are determined. An optional privacy impact indicator is determined based on how satisfying the request increases the current public information about the users. Crowds of users having similar attribute name/values are optionally determined. User and optional requestor privacy policies which associate threshold release criteria such minimum crowd size, minimum consideration with the non-public information are determined. A privacy agreement is reached for the disclosure of the requested non-public information based on the compatibility of the requester and user privacy policies. Privacy protecting transformations are optionally determined and applied to create crowds or groups associated with the requested attribute.

Abstract: Techniques for providing privacy protection are provided. A query is received. Privacy policy information, extracted knowledge and optional information about available public information are determined. Information about the knowledge extraction transformations applied to create the extracted knowledge and the source data is determined. Privacy protecting transformations are determined and applied to transform the extracted knowledge based on the selected privacy policy, optional information about available public information, the characteristics of the applied knowledge extractions transformations, the source data and optional previous user queries.

Abstract: A system and method for sharing files securely includes server software on a first device configured to communicate with server software operating on one or more other preauthorized devices, such as a second device. The servers communicate with each other securely using cryptographic information exchanged during a preauthorization phase using a range-limited communication channel. The server on the first device obtains file information from the other preauthorized device(s) and combines the information with local file information from the first device. This combined file information is sent to client software operating on the machine, which presents the combined file information to users.