Cryptanalysis and improvement of a certificateless encryption scheme in the standard model
We propose an efficient Certificateless Public Key Encryption (CL-PKE) scheme which is provably secure against chosen ciphertext attacks without random oracles. Our scheme is more computationally efficient than the existing schemes and provides the shortest public key length compared to other existing CL-PKEs with random oracles. We also propose a practical Self-Generated-Certificate Encryption (SGC-PKE) scheme based on our CL-PKE scheme. One of merits of such cryptographic systems is that it can be applied to countermeasure ``Denial-of-Decryption (DoD) Attacks" that is inherent in CL-PKE.