Broadcast encryption

Broadcast encryption is a category of cryptographic systems that are characterized by secure establishment of a encryption key that can only be established by a specific set of recipients defined by the sender, and where all communication is unidirectional. This allows the sender to securely address multiple users simultaneously by a single ciphertext, in which only the pertaining recipients are able decrypt the ciphertext, independently of each other. Since all communication is unidirectional, broadcast encryption avoids therefore the inconveniences of synchronisms and user interactions, which is the case for multiparty key establishment protocols. In this report we will consider the main categories of broadcast encryption, and in particular discuss some of the implications of stateless broadcast encryption.