Cécile Delerablée Pascal Paillier David Pointcheval Fully Collusion Secure Dynamic Broadcast Encryption with Constant-Size Ciphertexts or Decryption Keys. 39-59 2007 conf/pairing/2007 Pairing http://dx.doi.org/10.1007/978-3-540-73489-5_4 db/conf/pairing/pairing2007.html#DelerableePP07