Design of ID-based Contributory Key Management Scheme using Elliptic Curve Points for Broadcast Encryption

Broadcast encryption is the process of delivering encrypted data through a secure channel, intended for multiple users, in which only the privileged users can decrypt the content. In a broadcasting system, all the intended recipients are required to be accommodated in an organized way, which is possible through an efficient key management scheme. An ideal Broadcast Encryption scheme should define a key management scheme and an encryption scheme. The potential steps in key management are key generation, a perfect revocation scheme, and a re-keying mechanism. This paper describes a key generation mechanism using Elliptic Curves. The generated key can be used as a symmetric key. The important feature of this symmetric key is that the key is constituted by the contribution from all the legitimate users so that the revocation mechanism can be simplified, but at the expense of communication overhead. The proposed method describes two approaches to communicate the symmetric key to the users or to the groups.