Mahabir Prasad Jhanwar Rana Barua A Variant of Boneh-Gentry-Hamburg's Pairing-Free Identity Based Encryption Scheme. 314-331 2008 Inscrypt http://dx.doi.org/10.1007/978-3-642-01440-6_25 conf/cisc/2008x db/conf/cisc/inscrypt2008x.html#JhanwarB08