Abstract: The invention is a method for broadcast encryption that allows a broadcaster to send encrypted data to a set of users such that only a subset of authorized users can decrypt said data. The method comprises modifications to the four stages of the basic Cipher-text Policy Attribute-Based Encryption techniques. The method can be adapted to transform any Attribute-Based Encryption scheme that supports only temporary revocation into a scheme that supports the permanent revocation of users.

Abstract: The invention is a method for broadcast encryption that allows a broadcaster to send encrypted data to a set of users such that only a subset of authorized users can decrypt said data. The method comprises modifications to the four stages of the basic Cipher-text Policy Attribute-Based Encryption techniques. The method can be adapted to transform any Attribute-Based Encryption scheme that supports only temporary revocation into a scheme that supports the permanent revocation of users.

Abstract: A method and apparatus for repeated communication sessions between a sender (e.g., RFID tag) and a receiver (RFID reader) that employs a proactive information security scheme is based on the assumption that the information exchanged during at least one of every n successive communication sessions is not exposed to an adversary. The sender and the receiver maintain a vector of n entries that is repeatedly refreshed by pairwise XORING entries, with a new vector of n entries that is randomly chosen by the sender and sent to the receiver as a part of each communication session. Also, a computational secure scheme based on the information secure scheme is employed to ensure that even in the case that the adversary listens to all the information exchanges, the communication between the sender and the receiver is secure. In particular, the scheme can be used in the domain of remote controls (e.g., for cars).

Abstract: A method and apparatus for repeated communication sessions between a sender (e.g., RFID tag) and a receiver (RFID reader) that employs a proactive information security scheme is based on the assumption that the information exchanged during at least one of every n successive communication sessions is not exposed to an adversary. The sender and the receiver maintain a vector of n entries that is repeatedly refreshed by pairwise XORING entries, with a new vector of n entries that is randomly chosen by the sender and sent to the receiver as a part of each communication session. Also, a computational secure scheme based on the information secure scheme is employed to ensure that even in the case that the adversary listens to all the information exchanges, the communication between the sender and the receiver is secure. In particular, the scheme can be used in the domain of remote controls (e.g., for cars).