Signcryption Scheme with Standardized Verification Algorithm

Confidentiality and authenticity are two of the most important goals in setting a cryptographic system. A signcryption scheme, invented in 1996, is a new cryptographic primitive which can simultaneously achieve these two goals in one logical step. On the other hand, the standardization is always one of the crucial factors for practical uses for cryptosystems. Yum and Lee first introduced the need for public verifiability using standard signature algorithm. Following Yum and Lee´s work, in 2003, Shin et al. proposed a signcryption scheme in which the verification phase can adopt the standard DSA. However, this scheme is not forward secure. A forward secure signcryption scheme means that the private key of the sender does not help any attack to break the confidentiality of any signcrypted ciphertext generated by the sender. In this paper, modified from Shin et al. ´s scheme, we propose a new signcrypion scheme. Our scheme is forward secure and the verification phase can be done using the standardized signature algorithm, ECDSA. The efficiency and features of our scheme are compared with other schemes and the security of our scheme is proved in the random oracle model.