General and efficient Certificateless Public Key Encryption constructions

This work develops earlier ideas of Certificateless Public Key Encryption (CL-PKE) (posted on IACR ePrint 2005) and presents two efficient, practical constructions. Both schemes are shown to be key-escrow-free and strongly secure in the random oracle model. The paper also goes on to show that certain weak CL-PKE schemes can be transformed into stronger schemes, following on from this work. These are significant results for the growing number of public key applications where the communicating parties have no knowledge of each others certificate.