International Association for Cryptologic Research (IACR)
Abstract
Signcryption is a new cryptographic primitive that simultaneously fulfills both the functions of signature and encryption. The definition of generalized signcryption is proposed in the paper firstly. Generalized signcryption has a special feature that provides confidentiality or authenticity separately under the condition of specific inputs. So it is more useful than common ones. Based on ECDSA, a signcryption scheme called ECGSC is designed. It will be equivalent to an AtE(OTP$,MAC) encryption scheme or ECDSA when one of party is absent. A third party can verify the signcryption text publicly in the method of ECDSA. Security properties are proven based on Random Oracle mode: confidentiality (CUF-CPA), unforgeability (UF-CMA) and non-repudiation. Compared with the others, ECGSC presents a 78% reduction in computational cost for typical security parameters for high level security applications
