Benoît Libert Damien Vergnaud Unidirectional Chosen-Ciphertext Secure Proxy Re-encryption. 360-379 2008 Public Key Cryptography http://dx.doi.org/10.1007/978-3-540-78440-1_21 conf/pkc/2008 db/conf/pkc/pkc2008.html#LibertV08