Paper 2017/867

On the security of a Certificateless Proxy Re-Encryption Scheme without Pairing

S.Sharmila Deva Selvi and Arinjita Paul and C. Pandu Rangan

Abstract

Proxy re-encryption (PRE) is a cryptographic primitive introduced by Blaze, Bleumer and Strauss to provide delegation of decryption rights. A semi-trusted proxy agent re-encrypts ciphertexts under the public key of Alice into ciphertexts under the public key of Bob, without learning anything about the underlying message. In IWSEC 2017, Kuchta et al. presented a pairing-free certificateless proxy re-encryption scheme, and claimed that their scheme is the first to provide the certificateless property without resorting to pairing. They proved their construction is CCA-secure in the random oracle model, under the Computational Diffie-Hellman assumption. In this work, we show that the recently proposed construction of Kuchta et al. is vulnerable to several attacks.