ABSTRACT
This chapter presents broadcast encryption (BE). BE is a type of encryption in which the encrypted content is delivered over a broadcast channel in such a way that only the authorized users can decrypt the content. It can be considered as a revocation scheme where the revoked users find insufficient information to recover the key. Dynamic BE is then discussed in which the total number of users are not fixed. The preliminaries and the security model of the identity-based BE is then discussed. One important scheme regarding the identity based BE is the Delerabl e’s scheme. In any large scale public key infrastructure, there will be users whose private keys will be compromised. In order to mitigate damage that a compromised key can cause, any certificates associated with a compromised key should be revoked. The purpose of revocation is to inform relevant parties that certain certificates should no longer be accepted as valid even though they have not yet expired.
